Originally Posted by XavierRiley
... but I have played similar CRPGs such as Pathfinder: Kingmaker ...


IMHO that's the answer to how to limit long rests, right there. The most important point of limiting rests in Pathfinder: Kingmaker is that time is a factor because of plot events (you get better rewards for finishing earlier, or you get abducted by the evil lich who tired of patiently waiting for you to get to him). This increases immersion and makes it worthwhile for players to optimize their performence to avoid a lot of rests.

Systems that limit rests via items like food (Pathfinder) or camp fires (PoE) end up giving players pratically unlimited items anyway, because they don't get the balance right.

Systems that mostly restore all resources at the end of the fight diminish the tactical challenge (PoE, DA:O).

Pathfinder also gets the location right IMHO: You can only rest in certain areas (not dungeons, not foreign cities, not near enemies), you lay down the camp and there you are, while your companions do whatever they do at the camp.

None of this seems to be impossible for BG:3.