‏السلام عليكم If struggling with an addiction like video games but I vow “wallah I won’t play video games 1 week” (with a short time limit so it’s easier for me to fulfill) in order to force myself to stop - is this allowed? It sometimes works for me when I make vows like this but I risk kaffarah.

How about you limit yourself daily rather than quit altogether? You could dedicate one or two hours a day to yourself, and that would be your goal. You would schedule your time, focus on other things, and then, when you would like to relax and have some time for yourself, you would play for an hour or a couple of hours. The key is that you never exceed those hours.