Instead of having artificial limits just have the tadpole growing be an actual danger. (+the need items to rest mechanic).
Why introduce a mechanic that is disliked by most players? First of all, it is a game and should be fun.
Well the whole game premise is about you having a time bomb lodged into your brain and desperately searching for a way to remove it before it kills you. I'm not saying the game should have hard set time limits like in PF:Kingmaker (which I considered completely fine btw, although the game failed to explain they were in place when it was first released and that could force you to replay huge chunks of the game in order to suceed) just that some limitations for rest-spam whould be implemented otherwise suspension of disbelief is undermined along with internal ballance between classes.
Then you just increase the difficulty of the fights.
Probably the class balance will be sacrificed for a more enjoyable gameplay.
In games, the problem with time lapse is practically from the beginning.
When the game tells you that you must hurry to kill the evil dragon, otherwise it will burn the city in 99%, you have unlimited time for it. Gamers are used to it.
You can set a time limit even several times greater than needed by the average player, but he will feel that he must hurry.
The consequences themselves could even have a minimal impact on the game, but still most players would not hate it.
Gamers like to play games at their own speed.
Out of curiosity, I looked at a few topics related to pathfinder (I didn't play it myself) and it wasn't a well-liked mechanic, even though the game was aimed at more hardcore RPG fans.
I wouldn't be surprised if the next part would either abandon it completely or make it even less important.
I have a better comparison to PoE1 and PoE2 (I played both of them).
In the first game, the rest was limited to items which, on a higher difficulty level, you could have two with you.
This meant that you often had to go back for more.
As you might expect, it was not pleasant, so it was removed in the next part along with the combat system overhaul. Which didn't help the game anyway.
It would be appropriate for Larian to learn from other developer's mistakes and not try to smash the walls with his head.
Restriction may make sense in terms of role playing and logic, but both them fail with convenience.
Better to use the proven rest systems from previous D&D games than trying to invent a square circle.