If you have a system that CANNOT run games IT will NOT run games and there is no other solution other than upgrading, yes minor 1 to few FPS boost maybe possible but other than that it won’t fix anything. Cleaning your Desktop storage, and setting for best performance will help but still not enough to run games
Most new computers don't have the ultimate power plan anymore. If you can't find it then the "best performance " in the power plans is the best you get
That's not going to work. This will simply make your idle temps higher and you won't get any performance boosts. Your hardware unless tampered with such as via undervolts or overclocked is made to run on normal "power" consumption settings. Waste of time overall.