Challenging...

SATA is a lot newer than those distros. RH7 has a 2.2 kernel. AFAIK the first SATA modules cropped up in 2.6.19 (sata_promise module for things like the SATA150TX2plus, SATA300TX2plus). It might theoretically be possible to backport those modules to older kernels, but the whole scsi subsystem changed fundamentally between 2.4 and 2.6 (let alone 2.2), so you'd probably have to backport a lot more.

2 more practical options IMHO:
- run a later Linux that supports SATA (eg RHEL5 from 2007), should still work fine on an Athlon 750
- use a SATA-PATA adapter to run your SSD off the native - supported in old Linux - PATA controller

You could also try to run a more recent kernel on an older distro by building one yourself. If you really, really want to dive into that.

**Installing Gentoo in da club**

That is an interesting idea, I'll go with the SATA to IDE adapter to start with and try to get a newer kernel going from there. I may also go with Fedora Core 1 just because I use Fedora on all my more recent systems* so it'd be neat to have it on an old system as well, but that still only gets me up to Linux 2.4.

*: Not my PowerBook G4 because Fedora ppc32 isn't a thing anymore; it has LMDE Bookworm. And not my i5-2400 because it's been stored away since before I switched to Fedora; right now it has Windows Vista SP2 and Ubuntu MATE 18.04.