One issue with building Emacs from source, or more specifically my hack to ensure that the required system libraries are available on Aurora, is that in some situations the system version of Emacs “wins”.
For example, I wanted to experiment with running the Emacs daemon through systemd:
$ systemctl --user start emacs
Which failed to load my config correctly.
It was only after a closer look did I realise that despite specifying the --user flag, systemd was defaulting to the emacs.service file provided by the system emacs package in /usr/... and was therefore running Emacs v29 and not my v30 build.
But then I stumbled across systemd-sysext