1. You don't have to upgrade to windows 11 if you don't want to. A lack of security updates is beaten out by common sense every time. Plus there's always Linux.
2. If you're in a game jam team then you're already working for free unless you are explicitly being paid by said team. I also doubt the training AI would get from any game jam work would be substantial enough to be worried about, and if it is then you're generally improving on a tool that most anyone can use.
3. War profiteering is morally neutral at best. MS, while they are greedy to a fault, is not actually pulling the trigger on anyone. They are not morally responsible for deaths caused by people using their products. If person A uses an Apple Stabby2™ knife on Person B, that doesn't mean Apple is responsible for it. Person A could have just as easily used a sharpened stick if the intent was already there.