For me personally:
I'd get rid of fast travelling unless it's between actually different zones (let's say Surface and Underdark).
I'd allow long rests to be in specific actual locations on the map only. It should be either a camp (with a simple quest of establishing it, but it should be right there in the game not in some pocket plane) or in a camp of friendly npcs (an inn, a castle, etc.).
The main issue is that even with all that people would still go there and rest after every wolf/goblin and it would be nothing but inconvenience.
In real life dnd sessions it's usually story itself that limits long rests. But BG3 does not even have passage of time atm. And it most likely won't have it. We have to prevent hit-and-run-and-rest-and-repeat but people will still do it even if it's inconvenient.
The only actual solution to this problem I somewhat like is to have sub-zones (goblin camp, spiders lair, dungeons and so on) and its states - cleared/not cleared. If it's clreared, you can rest however you want (go to the camp or right there), if it's not, you can short rest right there, but you have to go to the camp for the long rest and in this case it's repopulated with enemies. And cleared state would mean deaths of all major enemies there. The problem here is people would kill the same named npcs several times which is bad also. Dunno, really. Maybe it should be just non-named npcs who repopulate the sub-zone after long rest. But in this case people would probably do kill-a-leutenant-run-long-rest-go-again.
