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