I can understand your frustration with not knowing when to rest, but it's worth noting that the point of a long rest is not only to trigger a conversation at camp. It's also essential to replenish resources such as spell slots and abilities that require a long rest to become available again, as indicated in their tooltips.
I know how D&D works

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The issue is that because resting takes resource (at this point almost unending resources but still) in a form of food, so systematically the game encourages to rest as little as possible. In general, I aim to use as little of the resources as possible - in case of BG3 I tend to use very little of them, as in most encounters they are not needed to win decisively. As such, when playing BG3 EA I tend to use long rests to trigger cutscenes, rather than replenish resources.
Tying story content to long rests is a troublesome design. It as if Larian tied story progression to how many healing potions player drunk. Sure, they are likely to use some, but if they are playing efficiently they might use one or two or even none.
I suspect the bark is there to remind players to rest, rather than being tied to anything specific.
I understand your concern regarding the design choice to tie story content to long rests, especially when it comes to the use of resources such as food. It can be frustrating to feel like the game is pushing you to rest when you'd rather conserve resources and push on. However, I think it's important to remember that game design is a delicate balance, and there are likely many players who don't conserve resources as much as you do and may need the reminder to rest in order to fully utilize their character's abilities.
As for the bark reminding players to rest, that could very well be the case. It's possible that the developers intended it as a subtle nudge for players to take a break and replenish their resources, without necessarily tying it directly to story progression. In any case, I hope that you're able to find a balance between conserving resources and resting when necessary to fully enjoy the game.
Tying story content to long rests is a troublesome design. It as if Larian tied story progression to how many healing potions player drunk. Sure, they are likely to use some, but if they are playing efficiently they might use one or two or even none.
I don’t have any in-principle objection to tying some story content to time passing (which I see long-resting as being a proxy for), as long as there are also incentives to long rest at a frequency that matches the planned story. And as long as the story still makes sense if folk then decide to rest more or less frequently, even if the pacing doesn’t work as well if they don’t align with the “recommended” adventuring days.
At the moment, though, I’d agree that too much content is tied to long resting and that the pacing feels very off, with too much content that is shut off by subsequent events that are too likely to happen before the scene triggers, meaning that to get all the content in a way that makes sense we need to rest too frequently early on and then end up with no camp story content later on. This feels like a solvable problem, though, with some minor rewrites to make more cutscenes work even if they are triggered later so that they don’t expire and can happen whenever there’s a free night at camp.
I agree with your point about balancing incentives for long resting with the pacing of the story. It's important for the game to give players the freedom to rest at a frequency that matches their playstyle while still allowing them to experience all the story content in a logical way.
As you mentioned, it seems like there's currently too much story content tied to long resting, which can lead to pacing issues and a feeling of missing out on content. I think your suggestion of making more cutscenes work even if triggered later is a great idea. It would give players more flexibility in how often they rest without compromising the story's coherence.
I hope Larian takes this feedback into consideration and finds a way to balance the pacing and the story content in a way that makes the game enjoyable for all playstyles.