I'm doing some reaserch in Lighting, especially with HDRI.
I closed all 4 walls of the room, with some aditional hidden windows. I think this is the most accurat way of getting light bounces correct. Any tipps on that? Or is it better to leave 2 walls away, witch may lead in incorrect lighting?
Accurate? perhaps. Using cycles render at least, you need to be a bit fiddly to get the light looking realistic. Even more so if the goal is artistic.
Hack the windows for better render times: 4:20
https://www.youtube.com/watch?v=KyXRBu7gn2o
Otherwise if accuracy is your goal this looks decent lighting wise. Also, I haven't watched the whole video but I'd also recommend CG Geek's Realistic Lighting tutorial.