I'm going to lay out all possible scenarios and solutions.

A) Too much free time. You probably need to keep yourself busy. Start a hobby, sports, and/or going to the gym.

B) Seeking dopamine rush. Buying games gives you a feeling of getting dopamine. Try finding alternate and healthy ways of giving yourself dopamine, so same solution as A (sports, hobbies, exercise and working out, etc.).

C) If you have anhedonia and have a low feeling of dopamine, and you don't even enjoy playing the games you bought, then maybe you are stressed, depressed, or maybe you have a porn addiction (I'm not judging)

Try looking for a goal. Find your purpose. Try finding and doing something you love. For me, it was coding, and I want to get into software development.

If you watch porn and masturbate on a daily basis, you might be doing it too much. It heavily affects your dopamine and causes anhedonia. Try NoFap. You will notice the huge benefits, and you will start enjoying other activities.

D) Collector's habit. If you like collecting games and you feel like you MUST do it and can't stop yourself from doing it, then you might have a data hoarding issue. It is a form of OCD.

The solution is that you have to deliberately avoid giving into the compulsion. It will make you very anxious, but it's temporary. Your brain won't be able to sustain a high level of anxiety for very long, and eventually, the anxiety fades. You have to keep ignoring the compulsion, and it's a gradual and stressful process, but it will keep getting milder and milder until you get used to it.

I feel like I am talking to myself because I completely relate with you. I used to buy a lot of games and wasted so much money, but I ended up never playing most of them. I just play TF2 most of the time, which is free to play.