Some hours ago, I stumbled across this:
https://youtu.be/gAEM2h_HZdI (skip to 4 minutes).
This is terribly unoptimized, but the whole idea is that (using a game file) you should beat both midbosses of Knuckles' LBZ as either Sonic&Tails or Tails in "different" acts (as in, beat one midboss, allow the transition from LBZ1 to LBZ2 to fully happen without dying, and then beat the second one) and after the second score tally, reset the game. The game file believes you are now in Mushroom Hill, effectively skipping the entirety of Launch Base 2.
I couldn't really find anything similar (other than a mention of the skip to the next level transition after a score tally glitch, which would often only save some seconds in an RTA/RTA-TB setting), so I'd like some opinions on whether this would be viable for the S3&K TAS (as you could effectively clear LBZ2 in 0:00.something).
Thank you!