This[1] is an up-to-date fork with sixel support, and a few other patches.
IMO it's unfair to compare barebones `st` with fully-featured terminals. The entire point of `st` is for users to apply their own patches to it, which does make it difficult to compare, since there's no standard version of it.
`st` is a pretty great terminal. I switched to `foot` when I migrated to Wayland a few months ago, but not for any practical reasons other than wanting to rely less on Xwayland.