I wish there were an alternative in a sane programming language that I could actually contribute to. For some reason PHP is extremely sparse in its logging and errors mostly only pop up on the frontend. Having to debug errors after an update and following some guide to edit a file in the live env that sets a debugging variable, puts the system in maintenance mode and stores additional state in the DB is scary.
Plus PHP is so friggin slow. Nextcloud takes noticeable time to load nearly anything. Even instances hosted by pros that only host nextcloud are just slow.
You could check out Frappe Drive (and Frappe, the framework it's built on, it's pretty awesome). They aren't accepting contributions at the moment but I'm sure that'll change once it's out of beta like with the other frappe apps. There's also Raven messenger also built on Frappe and you can use the two together (but without any real integration between the two yet, but that's on the roadmap on the Raven side).
I've spent a lot of time researching alternatives and NextCloud is the only one that does everything it does in one place. I've dug into the code a lot to find places to make it work faster and came out confused and mostly empty. It's also federated, and I think it's the only FOSS file sharing platform that is. It''s a very mature application so you'll be hard pressed to find features that are missing, but also to find things that could be further optimized without ripping out major chunks of the application which are likely interconnected with other major chunks of the application. For my personal use NextCloud instance I've resorted to just completely deleting the database and installing everything fresh between major versions, then just rescanning my local folder.
Hey, may I ask you a question? I really want to use Frappe Drive, but the thing is that I sort of need webdav and it's possible to use pibiDAV + NextCloud + Frappe. Do you know a way that I can use Frappe Drive w/ webDAV?
It's a bit hacky but I suppose there's always the option of using a separate WebDAV server on the directory where frappe drive stores its files. I haven't tried something like that, though. Unfortunately I don't know of any integration within frappe drive itself. Seems they're accepting contributions now so it's possible these will be implemented in the future. WebDAV is a bit of its own beast, though, so that'll be a huge undertaking in my opinion.