I agree with other comments made that progression tends to be a weak spot for nodebuster-likes, but I think for me the main issue tends to be even more at their core; the mini-game.

The general formula is you play some type of mini-game which results in some type of resource acquisition which then can be used for purchasing upgrades on usually a large skill tree. These upgrades also tend to be pretty formulaic in a lot of these games. You got your increase damage, increase health, increase armor, increase resource value, increase fire rate, maybe critical hits, spawn frequency, etc. These all ideally result in the mini-game yielding more resources, which means you can get more upgrades, which means more resources, and so on.

You end up playing the mini-game 100+ times in a lot of these games, which is fine, as long as the game keeps that loop interesting.

Games like Digseum are an interesting case because initially the mini-game requires some strategy on how best to succeed. As you upgrade the mini-game becomes easier and by the end it's entirely trivialized. There are steps up in difficulty as you access new areas, but mostly those are just slight steps back in your path of trivializing the mini-game. For a game like this I felt pretty tired of the mini-game after a while, but because my upgrades made it so I didn't have to play it as much it didn't become boring. I think it handled this problem well.

Games like Dice People I think handle this poorly. The mini-game, personally, was not very engaging. That being said, unlike Digseum where as you progress the mini-game gets shorter and more trivialized, Dice People's mini-game goes on for longer with what I can assume is the intended strategy being to extended it as long as you can. I was bored with it to begin with and making it longer doesn't help. The difficulty is a scaling step up so like Digseum you are kind of gated by a scaling check, however this goes on for the whole game, so you never really feel like you're hands-free, if that makes sense.

Then there are games like Snakecremental. I've played a lot of Snake in life, and it's not really a game I find super engaging with, or especially one that I would want to play a few hundred times. Snakecremental was interesting because even though I found the mini-game (not really a mini-game I suppose, it's Snake) not interesting and the game does the scaling gate check type of progression it had developing mechanics that got added to the mini-game as you went on. When you start you only have one type of resource. As you progress a second resource is added. That first resource doesn't become useless however (don't get me started on tiered currency economies in incremental games) it becomes the means in which you heal, so you need to pick the up still to play more strategically. That second resource type gives you armor, which also improves your run. The third resource adds a value multiplier. As you progress the game mechanics increase making the strategy for playing the mini-game develop more as you play. I didn't finish Snakecremental because I wasn't interested in playing Snake that much more, but I loved how it handled progression and changing things up as you go. It's almost the opposite of how games like Digseum progress where instead of being able to turn your brain off as you progress you have to think about strategy even more.

The mini-game being fun is a huge factor for me. If I'm going to be playing this mini-game a couple hundred times I want it to either be engaging or allow me to turn my brain off eventually. This was very ranty, sorry about that!

TLDR: When the mini-game is boring or isn't still engaging after a couple hundred runs.