I have something somewhat similar here: https://git.sr.ht/~tpapastylianou/misc-updater

The main difference is I initially only needed a mechanism to check if my "Manually-Installed or Source -Compiled" (MISC) packages have updates, but now it also supports install/upgrading too.

In other words, things I am forced to do by hand outside of a package manager, I now only do by hand once, save it as an 'install' script, and then incorporate it into this system for future use and to check for updates. Pretty happy with it.