This is not the issue. Of course you can try to wait for that. I say try, because wandering monsters are often a thing and chance can disrupt it.
Interruptions don't matter because the rest and recovery rules are so loose you can't backslide into a death spiral where more is lost than gained. With how low the bar is for short rest class nova to recharge & at will unlimited cantrip casting it probably doesn't even matter if the gm interrupts the rest with anything shy of rocks fall lightning strikes death by massive damage or an endless parade of ancient dragons opening with surprise air breath attacks.
All of that remains true until the gm trolling their players like that murders the session trying to stop players from taking the rest they feel entitled to and totally justified in taking.
The issue is whether there's a time pressure or not, and there almost always is.
The time pressure the players have already decided they don't care about? Making it matter dives into a whole different rabbit hole of areas that 5e designs against. Furthermore the GM can't be expected to apply super tight time pressure in every adventure till the game looks more like half minute hero than d&d without resulting in eventual burnout frustration and breakdown because the rest of the rules don't support it very well
Some people have been arguing that PCs know the mechanics because they can see what happens in the game world.
The only mechanic that matters though is after resting the PCs recover. Everything beyond that ihas fluff justification or the poster who accused players and game of engaging or allowing some kind of exploit in a solid set of resting/recovery rules
I won't sacrifice or save the campaign over it. If the group rests and lets the cultists prepare to the point where they can't win, that's their fault, not mine. It's my job to have the world react to what the PCs do or don't do as the case may be. It may very well be that the cultists are unable to prepare much in the way of defense. Or they may. I'd have to know the specifics of the cultists and that location to make an actual call.
You literally quoted the response to this or have admitted that the once per 24hr thing doesn't matter because the players will just wait it out if they ever crash into that after deciding to rest.
And rolling up only short rest PCs has other consequences. Long rest abilities are generally more powerful, which is why they aren't short rest abilities.
The purpose of rolling up short rest nova PCs is that it's almost impossible for their nova loop to be blocked by the gm shy of active inferno Forest fire type locations for adventures.
It really makes no matter to me. The world is going to react to what the players do or don't do, regardless of party make-up. I couldn't care less which classes they pick.
You miss why it matters, I linked to crapsack world on tvtropes because it describes the eventual result of the gm doing that repeatedly when players feel that a nova loop is the intended and totally justified way of playing. That being the players deciding the PCs never had a chance because the gm wants to run a terrible world where the PCs can not possibly ever succeed.
If the players look at consequences of their actions as punishments, they are too self-entitled for me to want to continue to play with. I'm not going to freeze the world so that a group of self-entitled players can have consequence free long rests whenever they want them.
The players would need to accept that any manner of playing other than nova loop alpha strikes is a reasonable or even intended manner of playing rather than some kind of killergm fueled punishment. Wotc has told those players that it very much is not intended or reasonable loudly and clearly by failing to support the gm with rules otherwise for over a decade now.
DM: "You finish the fight and are exhausted. Most of your resources are gone, but you still have some fight in you. You hear from beyond the next door the BBEG's voice..."
Players interrupting: "We take a long rest right here."
(24 hours later)
DM: ...say, "I know you are out there, come through the door and let's be done with this!"
Sorry, I'm not going to just freeze things so that the players can always be at 100%.
This is not even grasping the problem and just trying to blame someone for rest/recovery rules that drastically incentive toxic behavior from players who are given the impression that they are playing as intended