This is probably a dumb question, and maybe there is a way to do this with native applications, but I can’t seem to turn on a screensaver. One with the funky art just to run for a few minutes or so to remind me, hey you left the computer on, don’t forget to finish what you’re doing.
In synaptic there is: gnome screensaver, cinnamon, kodi, mate, ukui, screensaver, and a few others. The last one, Xscreensaver, was the one recommended when I searched online but I also found a forum post where it was mentioned this was no longer maintained and not recommended anymore.
I guess a more broad question is how does an end user using Synaptic package manager know if the package is actively maintained or likely abandoned? Stale is ok, but it seems like using a project that hasn’t been updated in 15 years could possibly be a bad idea for security.
xscreensaver is the gold standard for screensavers on Linux, even if the dev is a bit salty that people actually use his software on computers they want to control, and technically speaking the program is nagware, you just won’t (mostly) get to see the nags if you are getting it from your distro’s active repos.