Aside from the other follow-ups about whether or not to use them...
here's an example of a SPEC I wrote for a proposed package:
not all are concerned with building according to Fedora Packaging standards, for proposal
in inclusion
some of us use forgemeta because it provides capability that allows us to build what/when
we require
with capabilities approaching Opensuse's OBS. in any case, more flexible than not.
particularly the nice git branch support; incredibly useful, imo.
here's one of mine:
https://pagure.io/pgnd/nginx-mainline/blob/main/f/nginx/nginx.spec
used for my regular COPR builds.
it would be ... unfortunate ... if forgemeta were to vanish.
my $0.02