I would suggest Slackware, but may be a bit of work for you.
But if I understand you, OpenBSD may be the one. upgrades are simple, install is simple (unless you need GUIs) and patches are simple. I never had a patch break anything.
To upgrade non-base (installed) software just do a "pkg_add -u" once in a while. You decide when to do that. Plus docs are never out of date.
If you go with OpenBSD you should subscribe to mail list "[email protected]"
But you may or may not have hardware for it, if you have Nvidia Graphics, you really cannot use OpenBSD.
But if I understand you, OpenBSD may be the one. upgrades are simple, install is simple (unless you need GUIs) and patches are simple. I never had a patch break anything.
To upgrade non-base (installed) software just do a "pkg_add -u" once in a while. You decide when to do that. Plus docs are never out of date.
If you go with OpenBSD you should subscribe to mail list "[email protected]"
But you may or may not have hardware for it, if you have Nvidia Graphics, you really cannot use OpenBSD.
good luck