For the vast majority of my games, I'm switching to Level Up, since I like its additions to the 5e chassis better than the other options (expertise die, manoeuvres, strongholds, class rework with more exploration features etc.), and it's largely compatible with O5E (where I like almost everything pre-Tasha). Also, since it's still 5e, the majority of players around me can still be convinced to play it.
But in the background I'm working on my own OSE hack that brings a lot of 5e-like features to the B/X chassis (+ AD&D/Companion ideas to extend the rules to Level 20), and I'm hoping that once I finalise those rules, that will be my forever system. A D&D retroclone where I can port decades of old modules and rules options, updated with some 5e-isms.