Arial Black
Adventurer
Its not how the world works. The rules of the game of DnD are not a reflection of the objective reality of some alternate universe. Plus; 'DM'. You can spend all day 'short resting' as much as you want, but you dont get back squat unless the DM says so.
There are many things wrong with this.
In the past I have admired many aspects of your DMing skills, but this is not one of those times.
It is the way the world works. Although our characters have no direct conception of 5E game mechanics like hit points or spell slots, they certainly know about injury and healing, the limits of spellcasting, and the benefits of resting. The world of the PCs really does work such that resting heals you and refreshes casting ability.
The 5E rules are what controls the objective reality of our imaginary worlds. The inhabitants of those worlds cannot know about game mechanics directly, but the consequences of those rules impact their daily lives.
As for the idea that things in the game world only happen if the DM says so is misleading. If the expected outcome does not occur, there must be an in-game reason. If I rest for 8 hours, I get my full hit points back. If I don't, then something in-game must have prevented it. What? A curse from that necromancer we bothered? Those mushrooms we ate? What? The DM can come up with an in-game reason, sure, but D&D is not a game of 'Simon Says'! "Simon didn't say you got your hit points back!"
Come into my game and try and game the rest mechanic (or any other mechanic), and you'll find it doesnt work.
Oh, you mean, you cheat.
"Try and play chess in my house and see if your knight can jump over those pawns!"
Whatever the reality of the real world or the reality of or made up game world, it is what it is. If you regain Pact Magic slots by refraining from activity for 1 hour, then that's how Pact Magic works. It doesn't stop working just because you've adapted your behaviour to take advantage of reality!
This is true of any world, real or imagined. In the real world creatures evolve to take advantage of how their world works. They evolve their forms and they evolve their behaviour.
Most liquids expand as their temperature rises and contract when their temperature drops. One consequence of this is that when liquids start to freeze then it gets solid at the bottom first. Water is different: it contracts as it gets cooler, but at 4 degrees Celsius it expands instead. This results in ice forming at the top, creating ice sheets floating on liquid water. It is what it is. We can take advantage of that (by skating) even as we suffer from that (by ice damaging roads). But we can't pretend it doesn't work simply because we can use the reality to our advantage, or evolve our behaviour to adapt to this reality by inventing hotels in iceburgs.
In the 5E rules, and in the imaginary worlds governed by those rules, the reality is that pact magic is refreshed after 1 hour's inactivity. Therefore, smart creatures adapt their behaviour to take advantage of this reality. This is not cheating! This is not 'metagaming'!
If you stand too close to a fire it burns you. If you stand too far away then you are too cold. It is not cheating or metagaming to deliberately move to the Goldilocks zone of 'warm but not too hot'!
If you rest for an hour you regain your Pact Magic slots. It is not cheating or metagaming to rest for 1 hour in order to regain spent slots!
It can, and should, have realistic consequences for delaying for an hour when time is a factor. That is part of the resource management of the game. You make your decisions, factoring in time versus expedience. Nothing has gone wrong.
But it shouldn't have unrealistic consequences! The world works like it works. Resting for 1 hour does what it does, and cannot spontaneously fail, nor fail because the creatures in the game world adapt their behaviour to take advantage of how the world works.