The ironic part is… WoW ALREADY has this feature implimented and fully working.
Make yourself an alt, choose to start on that island place. You can instant queue in to that island’s dungeon and have AI bots doing the tank and healing for you.
No need to worry about toxic/elitist people, no GOGOGOGOGOGOGOGO, no “Do you have X achievement/score?”
Just go at your own pace, when you stop, the AI tank/healer stop. Want a coffee/etc break or had a phone call come in? NP, step away, the AI tank+healer is there waiting for you.
They should expand the system to the rest of the game, its proven to work and its part of the game already.