Not really an answer for packages that need configuration in /etc, add desktop entries to user's menus, or should be discoverable for example by systemd.
Adding to everyone's PATH is invasive and not really an option for most multi-user systems.
Adding to everyone's PATH is invasive and not really an option for most multi-user systems.
That being said compiling your own stuff in and of itself is not guaranteed to be a simple or "fun" task. It takes work and can lead to unexpected results: you immediately own anything that is custom on your system and become your own testing, debugging, and troubleshooting team. It isn't ideal.