Isn’t this slightly different, in that you are adding a know existing section.. your package section to the allowed sections.. and not checking that the section exists.. potentially from another package?
Though I guess it highlights a possible path, make sure you’ve added access to all the sections for the admin group.. or a migrationGroup and then allowedSections can be used as the section discovery?
I think so too, hardcoding it works for now, but yeah, I also couldn’t find any interface like we had in v13 (like ISection or ISectionService). I don’t know how they do it in UIBuilder there should be a way for c# to register it? as its done there.