I had also thought of this approach. It's kind of like the Inspiration system. You do a certain number of things and you earn some sort of Rest Points.

However, it does present serious issues, which is why it doesn't work. For one, if I REALLY did bad in a certain battle, and I absolutely need to long rest or I won't be able to continue the game, I'm doomed if I haven't earned enough points.

DM's have to be lenient when it comes to resting. They are supposed to be careful not to overtax their players too much. If the players have a really bad dice rolling day, and they get their butts handed to them, it is up to the DM to come up with a logical reasoning as to why it's suddenly okay to let them long rest.

Here's an example (I also posted this on a different thread also) that is completely outside of BG3 using typical Tabletop D&D:

Diadell and her companions learn that there will be a meeting between a lacky of a crime boss and a dwarf who is looking to pick up his money from a job he did. The meeting is to take place that evening, at midnight. In between, Diadell and her companions ran into a few fights, and they don't want to go to that meeting with next to no HP and spells. So, they decide to long rest. "Screw it," says Diadell. "If we miss the meeting, we miss the meeting. I'm not risking it."

So, not wanting the players to miss out on that opportunity, I, the DM, have an NPC friend of theirs arrive at the inn the next morning. "You aren't going to believe this," the NPC says. "I was in the slums at the meeting site where that lacky of the crime boss was supposed to meet with that dwarf who did that one job. There was a rival gang fight, and the whole thing was botched. Looks like the meeting is rescheduled for tonight. Thought you might like to know."

Suddenly, though they did something that should have messed them over so they couldn't complete the side quest, I, the DM, made it so that something happened to explain why that certain thing didn't fall through and so that they know they could still complete the quest. However, because of the rival gang fight, as a consequence for not going, I make it so that there are more gang members at the spot because they are expecting that there could be more rival gang trouble. Whereas initially, the encounter might have been easy, I make it slightly - SLIGHTLY mind you - harder to compensate for the fact that they decided to long rest. I originally built the encounter expecting that they would be weaker, so it wouldn't have been as tough. Now, however, because I know they are going to be tougher since they long rested, I increase the difficulty of the fight to make the battle more fun and rewarding.

Right now, the issue is that long rests in the game without consequences like this make every fight easier. That's not how good DMing works especially when the story says, "Quick! Never long rest because you'll turn into a monster if you do" or "Quick! Stop the druids from their ritual before they kick everyone out" or "Hurry, before the goblins attack and wipe out everyone in the grove." If the players are going to long rest frequently, then there needs to be some sort of complications and such that make up for the fact that they decided to reset all their HP and spells and such.

So, either create story side quests, like you have to save Rath because he stopped the ritual to buy you more time but now he's locked up by Kagha for his insolence, or you need to provide some sort of increase to enemy encounters or something to make them more challenging because the enemies were able to prepare more, or something like what I described above.

The entire trick to being a good DM is to create encounters that are challenging to players but aren't so nasty that the players get frustrated. The DM's job is NOT to try to kill the players. It is to create that exciting encounter where they have to strategically overcome the enemy and feel like heroes. However, if they allow players to just long rest all the time, and the encounters aren't tougher as a result, then the game is boring because the players just wipe out all the enemies.

I guess this is my point: If you are going to allow long resting all the time, that's fine as long as the encounters are all set to be challenging based on the assumption that the players are going to long rest after every battle, AND as long as the story isn't rushing you along to try to push yourself to NOT long rest, AND as long as you don't miss out on good story elements whether you long rest a lot or a little.

You see, I didn't have a problem with Neverwinter Nights allowing you to rest after every battle because there was no rush. If it took you a month to find out what was happening with the Wailing Death, big deal. No one was hounding you saying you were going to turn into a mind flayer soon if you didn't get your butt moving. If it took you a month to find out what was happening, that's just how long it took. No biggie.

The problem I have with BG3's resting system is that you are told by many, many characters, "What are you doing? Why are you long resting? Get your butt moving. We have a tadpole in our heads. We shouldn't be long resting. Oh, and by the way, if you don't hurry, the goblins are going to attack the grove and kill everyone and the tieflings are going to get kicked out because the ritual will be complete and the githyanki will probably go away and not be on the road where Zorru saw them, and so on and so forth. So whatever you do, don't long rest." Then, you ignore them and long rest and they're like, "Okay. Gith stayed where they were 6 days ago, ritual still isn't completed after a week - dang long ritual - goblins still haven't attacked, the lazy bums - and so on and so forth."

So, naturally, the player is urged to long rest very infrequently by everyone. And then, to top it all off, if you do long rest infrequently, you miss out on key story elements. You don't get as much character interaction and dialogue, Raphael may not appear to you until you are WAY close to the end of EA (happened to me before), dialogues get all jacked up because suddenly Astarion is a vampire spawn even though you never triggered the Astarion trying to bite you scene, and the whole thing winds up being a mess all because you thought you weren't supposed to long rest.

It's just a mess, and that's why it bugs the crap out of me. The camping supplies, though they seemed like maybe a good thing, and they stopped using food as healing items, which was good, is not the solution unless camping supplies are depleted more quickly and during short rests too. BUT... the issues still remain with camping supplies that you are encouraged to rest as little as possible, but character dialogues are then skipped entirely, some very important ones, if you don't rest frequently.

So, again, I think the only real solution is that they have to either change the story so you aren't so rushed, or they need to make it so dialogues are triggered outside of the camp AND they provide some sort of events that are triggered by taking too many long rests that at the very least explain why you have been given more time to keep going. Otherwise, it just doesn't make sense, and nothing really works.