I wouldn't have freaked myself out so much about it. I spent weeks reading articles, and watching videos about acoustic treatment, equipment, and excruciatingly detailed tutorials about the molecular makeup of every piece of material in your studio and in the end, these 2 things were the most important:
1) mix and master on multiple speakers/headphones: I used 2 sets of earbuds, 3 sets of closed/open headphones, 2 Bluetooth speakers, both cars, my Sonos, built-in computer speakers, iPhone/iPad speakers and of course my Rokit monitors.
The lesson being, learn how your room sounds because while treatment is important, you will never have a perfect listening environment.
2) make it somewhere you love to hang out in. My first iteration, I worried about optimizing the space since my room was tiny (9 x 11-ish) and I got to the point where I just hated sitting in that room. When I re-did it, I spent very little money but focused on aesthetics more than the first time around.