There certainly is a lot of overlap between the two. Homelab is a slightly older term, and has more of a hardware emphasis and makes me picture people with old

There certainly is a lot of overlap between the two. Homelab is a slightly older term, and has more of a hardware emphasis and makes me picture people with older enterprise gear (Dell R710s/R720s are perennial favorites among that group), older Cisco networking gear, actual server racks and VMWare based setups. Selfhosted is a bit more modern, and more software focused. More likely to be someone running a bunch of stuff on kubernetes across a bunch of Pis or an old desktop, with Unifi or Mikrotik networking gear