@Gooberking Sorry, I'm actually completely confused by your posts and what's going on.
If I am understanding correctly, you bought the
Mortal Kombat 11 Ultimate and
Injustice 2 Ultimate Edition 2-Pack on sale on your Xbox Series S, it wasn't installing properly, you're not sure they'll run on your PC, and you seem to think Game Pass charges you more to buy games?
Assuming I am understanding correctly, and to clarify how the system works:
Any game that's part of Xbox Play Anywhere, you can purchase via the Store on your Xbox console or via the Microsoft Store on your PC. When you buy one, you automatically get the other. This is irrespective of what level of Game Pass membership you have, or even if you have no Game Pass at all (which I don't).
Mortal Kombat 11 is an Xbox Play Anywhere title, however
Injustice 2 is not, so while
Mortal Kombat 11 will play on both your console and PC,
Injustice 2 will only work on the platform you bought it under.
Since it looks like you bought the bundle on your console, both games should automatically start to download and install. If for some reason they do not (and that's never occurred to me through the 19 games I've purchased digitally), you can a) go to the games respective page on the Store and select to install or b) go to your library, view your full library, and install it from there.
For your PC, you'll want to download the Xbox App, which you can get from the Microsoft Store. This functions as the "Xbox Launcher" similar to the Steam launcher, Battle.net launcher, etc. You can then either search for the game there and install it, or do so from the Microsoft Store App (and it'll ask you to install it form the Xbox App).
Game Pass also does not charge you more to buy a game, in fact you often get a discount for buying a Game Pass featured game (I think it's usually around 10% off). This is not always the case though, and you need to see if it shows if it's discounted or not when you're logged in and about to purchase.