I have some experience with some of these apps:

• open food/beauty facts: both have a long way to go IMO. The ui is very janky and lots of things don’t work. Open food facts seems to be a bit better but not much
• loop habit tracker: fantastic app, I use it every day, never saw a bug
• gadgetbridge: the ui seems rudimentary, but it has everything you need and it works really well. YMMV depending on which gadget you have though
• openscale: only used it for manual tracking. It’s very very basic but somehow I didn’t find a better alternative

I use ntfy and have no problems. It’s very reliable. No idea about graphene though

Have you tried Material Files (it’s on fdroid)? It’s genuinely great and it supports different remote protocols, although I haven’t personally tried this feature.

I don’t know about “simple”, but it’s very good. Been a happy user for many years

Wunderground was great before they got acquired by IBM

I totally get where you’re coming from and if there was a lean and stable app for files, calendar, contacts and tasks I would be very happy to check it out. But last time I searched there wasn’t anything I would trust.

Also, it looks like roundcube is now part of nextcloud 🤷

Fair enough, I guess, but what if I wanna selfhost?

This is great news! 👏

Honest question… Is there a better alternative?

It really isn’t. While the requirements are less strict than for the main repo, there is a review process to add a new app and I think they also have some automated checks. Additionally, Izzy (the maintainer of izzyondroid) is (was?) a member of the fdroid team.

Does this mean that every app there is legitimate? Of course not, but the same can be said about any other app store/repository.