Something else to test -
Close steam (not minimize or X, exit it entirely) - open steam/steamapps folder and see if there are any files starting with appmanifest_271590 - you can delete them ALL. Usually if you have problems installing you'll see some with .tmp .bak .old or whatever on the end. If you can't delete them, you could try moving them to a junk folder or deleting in windows safe mode. Then open steam and try again. If you have steam libraries, I'd check the steamlibrary/steamapps folder as well.

If that doesn't work after cleaning all the appmanifest_271590 variations out - I'd be cleaning steam/steamapps/downloading and temp folders of 271590 folders/files inside. (again, with steam closed - and possibly everything there if you have no dl's queue'd) - Quite possibly doesn't rule out other av/security/permissions/preventions.

Edit- too late now if you del'd the game (not sure what 'my GTA game was in the Rockstar games file' means - as steam version gtav very much prefers a 'steam / steamapps / common / grand theft auto v' or steamlibrary variation) - in the future if it appears to have uninstalled itself - you can fix the issue without 100gb redownload if files still exist - more info / most recent appmanifest update avail here too -
https://psteamcommunity.yuanyoumao.com/app/271590/discussions/0/133257324795538742/#c133257324795563877

Original link (one of) -
https://psteamcommunity.yuanyoumao.com/app/271590/discussions/0/3043858879858269578/#c3043858879858793483