First off, some really nice renders here. Nice composition/framing, use of Dutch angles, and above average lighting.
Answering your questioning about the brightness, I think it's pretty good, but I also have a fairly high end monitor. You have to anticipate that many are going to use be using darker/cheaper monitors that don't quite carry the range of light and dark needed for something like this. I'd probably make it a bit lighter and give it a bit cooler tone. Even just minor grading can do a lot for atmosphere in renders, or photo and flim.
Something like so:
View attachment 2412897