The smallest one that I'd say was truly epic was the penultimate stage of the Ronda Pilipinas, with Ronald Lomotos overturning a 9 minute deficit on his own teammate Ronald Oranza, after attacking his breakmates that he was monitoring in the queen stage to Baguio with a lot of serious climbing. Oranza had been happily letting Lomotos monitor the break even as the gap got dangerously large, then panicked and attacked his group solo over the last couple of climbs, seeing the time gap drop rapidly, but not quickly enough, as it became a straight shootout between the two solo-climbing teammates, and he fell 21" short - if the last climb was a couple of km longer he'd have held on.
I think Granon is the one though, while a case could be made for some of the others from an entertainment point of view, I think the combination of entertainment, expectation and significance makes Granon the winner, ahead of Torino. While the Granon stage was obviously a stage for action and Galibier north is an absolute monolith, I had the expectation that Galibier would largely be attrition and Granon would be where the action was, as its position in the mountain range and the fact it was followed by an Alpe d'Huez stage with three HC mountains meant I thought people wouldn't take too many risks in the stage until Granon itself lest they pay for it the following day, but instead caution was thrown to the wind, with Jumbo pulling off the kind of tactical masterstroke those of us who've known them since the Rabobank days thought was completely beyond them (especially after the masterpiece of failure-to-capitalise that was the 2020 Tour).