I figure it's time to switch to maintenance mode and just work on improving form, flexibility, smaller muscle groups, posture.

If you aren't going to a gym, I recommend getting some decent resistance bands, wrapping them around a sturdy pole and pulling them in different ways. You will work out moves for it. Some light ones at floor level to do leg raise-y kick-y type moves. Super effective. I have been doing it almost exclusively (at the gym) for a few months and it has been fantastic.

We're never really taught to think that far ahead in life and I think that's a frickin' shame. I'm going in late but not too late.

Massive shame. Our entire lives from childhood should be built upon good physicality at the core, and then move on to mind and emotion from there.