I played quite a bit before 2016 and now feeling the itch to play again. I enjoy theory almost as much as (maybe even more than?) playing. Having watched a few videos here and read some threads, I see so much emphasis on solver use and GTO. I want to play and get into theory again but I'm lost. There seems to be no structured content for picking up a baseline strategy on here and I find all of the focus on solvers a bit overwhelming because I am not going to buy pio (maybe I'll get GTO+ if it'll be helpful).

So how can I learn now? Any particular recommendations? As I'm playing micros NL5/NL10, which content should I check out to work on my fundamentals?