Do you find there’s a trade-off? I stopped using things like jj in insert mode because then if I recall, my j key would hang while waiting for the next keypress. Does that match your experience? And then I think there were a few times when I actually wanted to write “jj”. (Nice quick variable name, for example.)
So now I’ve settled on Caps-Lock set to Control (Mac) but additionally Caps-Lock without a chord or simultaneous keypress I have set to return to normal. That seems to work alright.
Ha, in the goofyness of my dreams I’d like some kind of Vim toe ring, ah, or maybe a sensor on the nose-rests of my glasses so that I could just scrunch my sniffer and return to normal mode. Come to think of it, I believe we’ve found original itch that Elon Musk is desperate to scratch, leading to his infatuation the ultimate in Vim remappings: brain-computer interfaces. First principles or mere yak shaving? 
As for Vim tips, I’m not a power user (and mostly use Vim bindings outside of Vim) but I’ve been enjoying getting familiar with registers.
At the same time I’m advancing very slowly because I fear being (again) like a kid at the procrastination playground of editor configuration, playing with productivity tools instead of being productive…