Room treatments are pretty boring. They just hang on the wall and not much fun to play with. But, as other’s suggested, I’d make these the #1 priority in your upgrade plan to improve sound quality.
I’d hang a better cartridge on the end of the tonearm.
IF the Rotel has digital output(s), a good DAC will add rocket fuel to your physical media.
You mentioned you’re in Montana. Sorry, just couldn’t help myself and added this link.