Incremental games are kinda nihilistic to me. I find a neat new one and get the rush of making progress, then a few days later the emptiness of it and existence in general hits me and I stop

I feel like overall opinion trends towards yours (I remember complaints about repeating the same content with little change for tiny boosts), but what people specifically consider too little a change, too tiny a boost varies. And if they have enough of other things they like in a game, they might put up with it, or deal with the problem by using automation scripts.

I can say I like when a prestige lets me do the content that took 3 days in 3 hours. I cannot really give a definitive answer on how I'd feel about taking 1 day to do what I did in 3. I did not finish Advent Incremental, but I can speak for what I have played so far. When you had to redo content, it didn't take that long (because the content you were redoing did not take so long in the first place) and it gave you a pretty nice upgrade afterwards. I tend to be a fan of redoing your past progress with a twist added in order to receive a bonus. Idle Formulas did this really nicely in my opinion, especially since your first go-around might take at least a day, but when you try to redo your past progress under specific limitations for a bonus, you are also expected to take 30 minutes or less to complete it.

I feel like the answer to this question is more of an art than a precise science, and that my answer is not too enlightening or good, but for the sake of engagement on this small community and on the Fediverse in general… I'm posting.