Honestly, I have no idea how to determine that. I'm a solo dev and not much of a programmer. I'll try to ask around.
The game is currently developed in Unity's HDRP, which requires Direct X11 or 12. I guess you'll need some newer rig (not necessarily high end, more like to support the modern shaders and renderers). There are some cases where people couldn't run the game or had low fps, and those people did run Witcher 3. I'm thinking about lowering the renderer to be more compatible with older computers, maybe even mobiles. But, as that would sacrifice the looks and would be a lot of work, I need to think it out.
Hope this was helpful.