I only watched the last installment in the series. It did a good job of summarizing the progression and I see the series as really advancing the topic of room acoustics being more important than much of the gear.
I really appreciated Ron’s closing remarks about expectations for improvements in the viewers rooms. Ron started with a large echo chamber with a lot of room to add treatments that had audible but to my ears progressively less obvious impact.
Available resources will match the depth you’re willing to go.
+1 on Acoustic Fields videos. Among others, I also really like
https://acousticgeometry.com/videos/. GIK also has a lot of good Acoustics 101 info.
They’re all educational but also designed at some level as marketing material to sell products.
This Audioholics article focuses on small room acoustics, which Ron’s room probably isn’t.
https://www.audioholics.com/room-acoustics/room-reflections-human-adaptationIt includes an embedded video discussion with Matthew Poes whose work definitely influenced my approach, though probably too late for me to avoid spending a few misguided treatment dollars.
If you’re up for it I’d definitely recommend investing time and relatively little money in REW and a measuring mic. The recommended UMIK 1 or 2 are easy choices. Measuring before treating will help identifying specific room problems and target treatments or other fixes (DSP, subs).