Steam works very well on Linux. There is a setting in Steam to enable 'proton' for all games - this allows you to play Windows games on Linux without having to do anything else. It has worked flawlessly for every game I've tried.
As for your movies thing, I don't know. I deliberately avoid software that automatically searches and catalogues stuff on my computer. So I'm not sure how easy it is to do what you are asking for. It's something that I'd avoid rather than seek out.