I recently bought Sims 4 on my Xbox One s and now wanted to know if I can somehow get it over to my pc, because I would rather play it on the pc, or do I have to buy it from scratch now? Or can I transfer the game from my Xbox to the pc
No. This is not possible.
With an Elgato you could transfer Sims 4 or your entire XboX video output to your PC. E.g. Select the Elgato in OBS.
You can find a lot of videos on YouTube about Elgato and broadcasting.