Amphorus was all about a year long update arc with deep lore and people got tired after 3 versions.
I would make the argument that story presentation also matters quite a lot. I get that it's a gacha and time retention is a must, but MHY isn't really doing themselves any favors with how bloated the dialog feels, how meandering it is, or how you can't skip or even click through text fast enough.
It makes it tedious and can really kill any interest in the narrative, at least for me.
Not to mention, in my humble opinion, Amphorus, despite aspects I like about it, is really fucking okay-ish storywise. It's telling to me that there have been so little discussion about the story in this thread.
And even I can't say anything about it aside from some complaints and some faint praise because it's really not interesting. It's just there.
Granted, it could be worse. And I'm not expecting Berserk levels of intensity here either. But MHY can write good stories. Sumeru and Fontaine proved that. I'd say early ZZZ proved that too because it had fun with itself and it worked, despite the grim undertones.
Edit: Actually does ZZZ have any deep lore? I get the impression it's not as compact at Genshin or heaven forbid Star Rail, even if there is an archive and there's the whole Void Hunter (smells like the fucking High Cloud Quintet to me. Oh god please no) and whatever else.