I have Game Pass Ultimate through July 2027 and it doesn't affect how I buy third party games unless they're on Game Pass Ultimate day one. It's all about day one for me because im not waiting to see if/when a game I want to play goes on Game Pass. I did however buy the Premium Edition of Starfield.
I am a subscription guy though and do prefer subscriptions over buying games due to the fact that I rarely replay games, don't care about ownership or collecting games. For example, I use Ubisoft+ on Xbox for their games where as before, I used to buy them all day one.
With that said, I do buy games. Bought Visions of Mana and Warhammer 40,000: Space Marine 2 digitally on Xbox recently as well as a few Call of Duty games that were on sale two weeks ago since I skipped them but after completing Modern Warfare III last year and looking forward to the Black Ops 6 campaign, I decided to buy Black Ops Cold War, Vanguard and Modern Warfare II. Also bought Scarlet Nexus, Star Ocean The Divine Force and Crisis Core Final Fantasy VII Reunion but not sure if I will ever play the first two games.
Next new game purchase and last for 2024 is the upcoming Dragon Age: The Veilguard which is looking more and more like my 2024 game of the year. Can't wait!!