Keep a minimum of 30GB free, for Windows update processes on the windows system partition. I don’t how much the windows installation counts in space, but add that to the 30gb free space. I would recommend to have a extra partition for the games on NTFS and move your steam, epic, ubisoft, whatever library to that partition.
I have tried to use the same gaming partition between Linux and Windows, but failed every time. In the worst case this can alter your Windows privileges. At least I had this issue.
Currently I’m using Windows only for 2 games: Space Engineers and Empyrion. The rest works with better performance on Linux. Satisfactory, Ark survival, Elder Scrolls Online have more FPS on Linux with the same settings. I have to use a nvidia 1050 Ti in my laptop. With a AMD GPU the situation is a lot better on Linux.
I’m not a hardcore gamer, mostly im coding here and there. But sometimes gaming is a must have.