Probably last tested last year with NomadBSD (FreeBSD-based). It was literally 30 seconds to resume.
OpenBSD is faster, about 6-8 seconds, at least on my old x200. Not as fast as Debian, but fast enough.
But I haven't tried it on a ton of different hardware. I think I've tested FreeBSD (via #NomadBSD) on my three thinkpads: X200, X260, X390 Yoga)
Not sure about the last one, as I just got it this year.