No: It's not Denuvo.
Denuvo is not the reason this, or any game other than RE8 (and that was Capcom ♥♥♥♥♥♥♥ with it adding their own layer of drm on top) run worse. Shader compilation stuttering is a plague on modern pc gaming caused by increased shader complexity on modern systems, the adevent of raytracing, DirectX12 and the terrible way Unreal Engine 4 handles shader compilation. Since it's not a problem on console and there's no one-button fix for it, many devs dont give a crap and saddle us with this. They have to implement either, a way to precompile, or an asychronous compiler. And they dont want to deal with that. This is devs ignoring a serious problem that mostly occurs with UE4.
The good news is the problems in this game seem to stem only partly from shader compiling, part from THE DAMNED 2K launcher, which opens the wrong version of the exe instead of the 64 bit executable. Plus, there seems to be trouble with the cloud save files. And the download cache helping the stutter somehow. Problems all around, but Denuvo isnt one of them.

• Right click the game on your Steam Library, highlight Manage and click Browse Game Files
  In the game folder, go through these folders:
  MidnightSuns -> Binaries folder- >Win64
  to find MidnightSuns-Win64-Shipping.exe
  
  
• Copy the filepath to the exe,
  if you dont know how here's a way:
  Click the Windows Address Bar on top, add a \ (alt+92) and copy the suggested filepath for the exe
  
  
• Right click the game on your Steam Library. Select Properties and paste the filepath we copied in between double quotes "" and add a space and %command% at the end
  
  Example of what this will look like:
  
  “D:\Program Files (x86)\Steam\steamapps\common\Marvel’s Midnight Suns\MidnightSuns\Binaries\Win64\MidnightSuns-Win64-Shipping.exe” %command%
  
  
  Clear Steam's DL Cache
  
  
• Go to Steam Settings (top left of steam Client, Click steam, then Settings.) ->Download and click Clear Download Cache. Log back into Steam
  I know it doesnt really make sense that this helps but it somehow does. Something weird, this game.
  
  
  Additional Settings
• Go to the in-game settings and TURN OFF RAYTRACING. It's busted.
  
  You should be good to go.
  
  If you are still having problems try:
  
  
• On the Nvidia control panel, Change settings for this game and turn Low Latency to Ultra, and Energy Profile to Maximum Performance. (If you dont know how to use your driver's control panel, don't.)
  
  
• You can also try, to set the renderer to Directx11 by adding -dx11 in the command line, DX11 does not generate shader caches. But YMMV as it may slow down the game in a different way, and I do not recommend it
  
  
• If you still experience stutter, try resetting graphic and video settings to default and then changing them again to what you were using.
  
  
• I recommend not vsyncing this game

The game apparently gets confused about the path to save files. Especially if you started before removing the launcher and then came back to the game. Or tried using cloud saves. Reports are mixed but, here are some fixes:

If you cant find your saves, chances are the game created another folder, you need to move the files from one to the other

Default Save game data location:
Windows
Linux

So, as reported by user wyndhambarnhill

Originally posted by wyndhambarnhill:

go to %USERPROFILE%\Documents\My Games\Marvel's Midnight Suns\
There may be two directories.
Go to the steam one and copy the savegame directory to the other one.
Check the content of the directory before, must have one file per save.

Your antivirus might be the problem, as reported by cvendeen

Originally posted by cvendeen:

I resolved the issue by going to virus and ransomware protection and allowing the steamapps/common/Marvel's Midnight Suns/Midnight Suns/binaries/Win64/MidnightSuns-Win64-Shipping.exe application through controlled folder access. I had previously allowed the application in Steamapps\common\Marvel's Midnight Suns\MidnightSuns.exe access, but that wasn't the correct executable. I also bypassed the 2k launcher, which may have been confusing the ransomware protection. Now I see a save file folder inside the Saved_Steam_[UserID] folder.

For those having problems syncing saves:

Originally posted by nilus:

For me it created the save location "\Documents\My Games\Marvel's Midnight Suns\Saved_Steam_[My Steam-ID]", which it also synced to the Deck. But on the Deck my Steam-ID was empty and it created the folder "Saved_Steam_", which was not synced.

"Saved_Steam_[My Steam-ID]" kept getting synced, but the game accessed "Saved_Steam_".

As a work-around I created a symbolic link in \Documents\My Games\Marvel's Midnight Suns:

ln -s Saved_Steam_[My Steam-ID] Saved_Steam_

Don't forget to rename/move "Saved_Steam_" before creating the link.

Originally posted by Jack Porkins:

Save folders for this game are a friggin mess. I've come across four different folder names that all arise from normal or semi-normal situations:
Saved :: occurs on the steam deck if you bypass the 2K launcher using instructions above. Haven't tested with vanilla linux yet.
Saved_Steam_ :: occurs on the steam deck while using the 2K launcher
Saved_Steam_${steam_user_id} :: "normal" "correct" folder that gets used when I play on Windows. Also used via remote play if you've bypassed the 2K launcher.
Saved_Steam_-- :: folder that gets used when trying to use Remote Play with the 2K launcher in place.
I've been able to keep my saves working properly on the steam deck side by creating multiple symlinks that point to my user ID folder:
## replace ${steam_user_id} with your numeric Steam user ID
# ln -s Saved_Steam_${steam_user_id} Saved_Steam_
# ln -s Saved_Steam_${steam_user_id} Saved

Keeping the 2K launcher disabled on my windows machine lets the game use the correct save folder while using remote play, so I'll be operating that way moving forward.

On Proton, the launcher removes itself out of the way since a patch to make 2K games playable again, but given how much performance is improved on Windows, we might wanna remove it too

Warning: Crashing on day end/going to sleep is still a known issue that many people cant seem to get rid of

Steam Deck Only:

Fixes by CryoByte33

are necessary at least as of the time of writing:
16gb Swapfile, Swapiness set to 1, vram set to 4gb
Instructions: https://www.youtube.com/watch?v=od9_a1QQQns

In game open the ... overlay, and on performance, advanced, manually set the gpu to 1400.

Additional Deck Settings at the end of guide


Put this on the Steam Launch Commands

Command by user Calvin.



Saves Location:
/home/deck/.local/share/steam/steamapps/compatdata/368260/pfx/drive_c/users/steamuser/ MyDocuments/My Games/Marvel's Midnight Suns

• Go to desktop mode
  
• 
  
• Navigate to /home/deck/.local/share/steam/steamapps/compatdata/368260/pfx/drive_c/users/steamuser/ MyDocuments/My Games/Marvel's Midnight Suns
  
• 
  
• 
  
• while inside the Marvel folder you will see 2 folders one named Saved_Steam_ and another but with a bunch of numbers after it that is your Steam ID (look below, there might be different names)
  
• 
  
• copy the name of the folder that has your steam id and while your in the folder with both saved_ and saved_steam_number (MyDocuments/My Games/Marvel's Midnight Suns)
  
• 
  
• enter ln -s Saved_Steam_[My Steam-ID] Saved_Steam_
  
• 
  
• Look inside the last folder, you will see a link file. Rename it to whatever so you can move it without overwriting.
  
• 
  
• Move it one folder up to the /home/deck/.local/share/steam/steamapps/compatdata/368260/pfx/drive_c/users/steamuser/ MyDocuments/My Games/Marvel's Midnight Suns folder
  
• 
  
• Delete the folder Saved_Steam_
  
• 
  
• Rename the link you made to Saved_Steam_

Originally posted by nilus:

:
For me it created the save location "\Documents\My Games\Marvel's Midnight Suns\Saved_Steam_[My Steam-ID]", which it also synced to the Deck. But on the Deck my Steam-ID was empty and it created the folder "Saved_Steam_", which was not synced.

"Saved_Steam_[My Steam-ID]" kept getting synced, but the game accessed "Saved_Steam_".

As a work-around I created a symbolic link in \Documents\My Games\Marvel's Midnight Suns:

ln -s Saved_Steam_[My Steam-ID] Saved_Steam_

Don't forget to rename/move "Saved_Steam_" before creating the link.

Additional instructions and clarifications here:
https://www.reddit.com/r/SteamDeck/comments/zadtvj/comment/iypn9o9/?utm_source=reddit&utm_medium=web2x&context=3

Steam Deck Only:
Fixes by CryoByte33 are necessary at least as of the time of writing:
16gb Swapfile, Swapiness set to 1, vram set to 4gb
Instructions: https://www.youtube.com/watch?v=od9_a1QQQns


Settings (by user u/Literally_Sticks on Reddit):
*Set Manual GPU Clock to 1400
*Apply the following settings