Why when I want to buy this game, steam says that Nascar Heat 5 is no longer on steam?

The "2020 Season Pass" says "...You will also receive the Tony Stewart content that includes Tony as an option for the in-game spotter, an exclusive Career contract offer from Stewart-Haas Racing, and classic Tony Stewart paint schemes!" But can we get the same items as the above when purchasing the "Ultimate DLC"?...

UPDATE (6.29.23): A fix has been deployed for those who were unable to access the Next Gen Car Update content after purchase. You will now be able to experience the Next Gen cars in NASCAR Heat 5. Thank you for your patience! _____________________ (6.22.23) We are currently aware of an issue with the Next Gen Car Update release and working towards getting you in the game as soon as possible. We will provide an update as soon as we have a fix. Thank you for your support and feedback! - Rusty / Community ...

please FIX! this dlc no longer is working, i should have for example 13 skins for Chase Elliot i have only 9 now. Jimmie Johnson should have 11 Skins, now i have only 3. every other dlc seems to work but these.. WTF! seems to be bad file(s)?? NASCARHeat5_Data\StreamingAssets\PC\AssetBundles\CarAppearances\mastercarappearancelist.rab NASCARHeat5_Data\StreamingAssets\PC\AssetBundles\CarAppearances\mastercarappearancemap.rab...

Nascar, does this mean all of this series 3,4,& 5 are gone? I've been trying to reinstall them and I keep getting corrupt disk.