We do not automatically branch everything from one release to another. We have found that trying doing so pisses off a lot of the volunteer maintainers who are doing EPEL in their spare time and don't want added work they didn't sign up for. Packages are put into a release when a volunteer maintainer knows that the package is wanted, and they have time to do so. If you need a set of packages, go to
https://bugzilla.redhat.com and check to see if there are outstanding bug tickets requesting a maintainer to support it in EPEL-8. If there are add your info to that ticket, if there are not please open a ticket.