As title says, the tab unloader should have an option to automatically suspend tabs based on inactivity time alone.
I've found that the current unloader based on automatic memory usage estimate is kinda lackluster and it feels like often it simply doesn't work, an option to simply unload the tab after X minutes of inactivity would probably be better for most people.
There are several extensions who do that, but it would be great to have it as a native feature https://addons.mozilla.org/en-US/firefox/addon/new-tab-suspender/?utm_source=addons.mozilla.org&utm_...