I own a Quest 2 and what I do is keep my Quest fully charged and have it plugged into a 20k mAH powerbank while using it.
If you keep it hooked up to a powerbank while its at full charge your Quest won’t get boiling hot from charging itself and you will have a battery life of atleast 8hrs (if your VR sessions are somehow longer than this…lol)
The obvious downside is that this is only viable if you use your Quest via Airlink.