This could easily be simply because Pacman doesn’t do as much as apt. For instance apt tracks symbols exported by shared libraries. Pacman doesn't.

I've never heard of that. In what situations is that tracking used?

As far as I know, only RPM-based package managers do symbol tracking at dependency resolution time. Neither Debian nor Arch package managers do this.

I think Void's is faster. Less ergonomic though.

Would be fun to see some benchmarks.

Agreed, so is "apk" from Alpine Linux.