Spotted a few optimizations, next thing I know I've spent the rest of my night (and staying up way too late) going through the entire TAS to looking for optimizations and resync RNG states after each one.
Round 16: Start holding Right slightly later (frame 11088) at the end while waiting for the yellows to clear, so that Toad doesn't start climbing the yellow stack before the hitboxes clear. No time save, just looks cleaner.
Round 26: Optimized movement starting at frame 19904. I move Toad right then hold Down to let the white bomb fall before I set off the chain, thus saving some time after the chain resolves. Unfortunately I can't simply drop the white bomb ahead of time, as it would match prematurely. Time save: 16 frames.
Round 34~36 (frames 29041~31922): I originally forgot the victory animation skip in round 34 and 35, but when I added them back in, the RNG state desynced. I originally thought this was unrecoverable, but I came back to this and managed to find a way to sync it back up. Time save: 113 frames.
Round 59~61 (frames 60676~64345): In R59, I figured out how to adjust my movements in a way that allows me to manipulate the green bomb to spawn in the middle column. Unfortunately this also advanced the bomb color seed one time less, which desynced the RNG state in R60, but some movement optimization and I was able to add enough frames of holding Down to make the RNG state catch back up. Then R61 changes were mostly getting the fairy position RNG state to sync back up, plus one movement optimization prior to spawning the red diamond. Total time save: 100 frames.
Round 66 (frames 71036~71356): Small movement optimization by picking up the cyan and blue and pressing Up to get on top of them instead of climbing up by holding Right. This saves 3 frames and looks cleaner, but I lose the 3 frames at the end of the round to manipulate bomb spawn positions in R67. So no net time save, but it still looks cleaner.
Round 69~70 (frames 75155~756329): Another movement optimization by letting the top yellow monster fall instead of walking underneath it. This saves 11 frames in Round 69, but forces me to lose 10 frames to manipulate luck in Round 70, so in the end this was a lot of effort to save a whole 1 frame.
Total time saved: 230 frames