Updating this thread for closure.
During the first stretch of sunny weather in early 2021 I replaced the leaking intake seals, the spark plugs, and the ignition cables then TPS reset. The bike hasn't stalled since and obviously rides way better.
The only mystery I never solved was the dropping AFV%. At the time of seal replacement my AFV was 61.7% (normal operating range is supposed to be 95-104%). Even after the above repairs the AFV would drop from 100% to 85%. It wouldn't stall at 85% or go lower but I could feel the power loss.
With everything else sorted I think the only culprit for an 85% AFV would be the O2 sensor? To be honest at that point I couldn't be bothered to drop the engine to access the O2 sensor; I just wanted to ride my bike. Instead my dirty hack was to disable open-loop learn with EcmSpy to freeze the AFV at 100%. The bike has run great ever since.
If running with open-loop learn off is exceedingly terrible long-term come yell at me and maybe I'll come back for round 2. Otherwise bite me. Just kidding love you guys and thanks for the help.
