For room treatment, I really like Jesco from Acoustics Insider.
https://www.youtube.com/@AcousticsInsiderHe's got a lot of videos on how to handle room acoustics as well as how to read/use the measurements from REW, as well as tips on how to build absorption panels/bass traps as well as placement.
Lots of great info to dig into.
He mainly focuses on small-room or home-studio settings, but a lot of his info can still be applied to home listening rooms by focusing on the main and secondary reflections, front wall and ceilings, etc.
When it comes to absorption panels, he recommends using several 2'x4'x6" thick panels stuffed with rockwool or fiberglass which is spaced about 4-6" off the walls which will help with wavelengths down to ~200Hz.
In order to be effective, you'll probably need more panels than you realize, same goes for diffusion panels.
A really good series of videos to watch was his collab with Music City Acoustics that goes through measuring a raw room with REW looking for the best place to sit, as well as how the acoustics change as you add more and more treatment to a room:
https://www.youtube.com/watch?v=kTOD5DUW9Ak&list=PLVisTZxdtuNQCPXt6mPuHW1szj4kAIOSV