A lot of things have changed in the 64 bit update, and as with most things, the experience on Linux is always the buggiest. In this guide we'll address some of the problems as they arise. As such, this guide will be a work in progress.

The first thing you'll notice upon loading into a match in the new update is that your sensitivity feels very slow.

This of course is a problem that only we on Linux experience. Luckily theres an easy fix.
For example, if your sensitivity was 1.00 in the old version, use 1.50, or if before it was 2.00, use 3.00.
Since this is what most people are here for, I've made it big for you.

If you use a weird sensitivity like 3.42, an easy way to figure it out is to go into a scientific calculator and divide your current sensitivity by 2. (3.42 / 2 = 1.71) Then take that new number and add it to your old sensitivity. (1.71 + 3.42 = 5.13). Simple

Along with the sensitivity issue, you'll notice that a lot of the text in game is BOLD and in a different font.
Here I'll post some side-by-side comparisons at the same resolution.

In-game chat


Killfeed
There are other places where this happens like the inventory, menus, etc...

But you already knew this, which is why you're here to fix it. Unfortunately, as this update is still fresh off the press, there is no known fix for this yet. I'll update this when one is found. (Unless this change to a new font is intentional, in which case, there may not be a fix)

The 64 bit update is definitely and upgrade from 32 bit, but lot of people still only play TF2 because they have really old/slow computers, and this update shouldn't change that fact too much, but nonetheless will. (after all... they added a whole 'nother 32 bits the the game!)

The band-aid method right now is to go into your visual settings and turn everything back down to Low (or whatever you had it at before). The update reset a lot of people's settings, even on Windows, but this should get your game back to a nice crispy 60fps.

Settings > Video > Advanced
Before

After

I personally did not have this problem. But if you are, try adding -window to your launch options in TF2

Go to your Library, right click on TF2, and go to Properties



And add -window to your launch options


If this doesn't work, in that same menu, try switching the launcher from Standard to Legacy

Hopefully this works for you, if not, there's another method
(Thanks to lightwo for the fix)

Another possible fix, if you're using the flatpak version of steam, is to NOT use the flatpak version of steam.
You can do this by going to your package manager and install steam from there, if it's available. Otherwise, if you're using a Debian-based distribution, you can go to the Steam website and download the .deb file to install steam that way.
(Thanks to CruZerO for the fix)

Apparently these fixes are hit or miss on the Steam Deck, and I don't have a Deck personally so I can't confirm, but here is a fix by someone in the discussions. This may also work for standard desktop Linux so here goes
(Thanks to abyrvalg for this fix)

There are definitely more bugs to squash in the future and I hope to at least have helped some of you. I know some Linux users cant even launch the game right now, so leave a comment describing your issues and I'll add them to the list

Right now this is intended as a quick fix to get people back into and enjoying the game, so get out there and have some fun.