I tried Nextcloud a long time ago. It was buggy. I really, really wanted to pay for it at the time, but it didn't quite work.
Should I try it again?
I also might be confused, but I thought they kept some key parts proprietary. I'm now looking, and that doesn't seem to be the case. Perhaps something changed (perhaps even my memory!). I'm a lot more happy to pay for 100% open-source than 90% open-source. Is it fully open-source?
I'd love to pay for a reliable, hosted, open-source solution.