Please branch and build sendmail in epel10. If you do not wish to maintain sendmail in epel10, or do not think you will be able to do this in a timely manner, the EPEL Packagers SIG would be happy to be a co-maintainer of the package; please add the epel-packagers-sig group through https://src.fedoraproject.org/rpms/sendmail/addgroup and grant it commit access, or collaborator access on epel* branches. I would also be happy to be a co-maintainer (FAS: orion). This is needed for clamav-milter. Current rawhide appears to build fine in epel10.
Branched and built.