Nextcloud is intended to be self hosted in order to be private. I don’t recall Nextcloud having end to end encryption, but I know it has server side encryption. On the Nextcloud website, there are providers who host Nextcloud for you.
If I choose to go with Nextcloud hosted by one of these providers, is my data visible to them? How is the privacy different compared to self hosting it? In such a case, should I opt for an end to end encrypted solution like MEGA or Filen?
Disclaimer, I have never used Nextcloud. With that said, my understanding is that the option for server side encryption is configurable by the server admin. My understanding is that if you use Nextcloud with someone else hosting it, they can disable the encryption at any time. So you are trusting a complete stranger to not turn off the encryption and even if they are good humans, they could also just have mis-configured things.
Nextcloud seems pretty cool if you want to self host, but I would advise against going with someone else as the host. The New Oil has a pretty good youtube video on this topic.
Mega and File.n are also possibilities. I personally would only trust Proton to do this correctly but Proton Drive is really not a usable product for most use cases. And I say that as a pretty big Proton Mail fan boy.
I would advise you to consider Cryptomator plus whatever cloud provider you want. I personally use Cryptomator with Google Drive. Not to everyone’s taste in the privacy community but it is a totally valid option and the day-to-day usage is really easy. If you are not familiar what Cryptomator does is mount a virtual drive inside a normal commercial cloud provider (or anywhere you want, including locally or on an external drive) and encrypts everything at the file level on your device before sending it to the cloud provider. Desktop versions are free but mobile versions are a small fee. I think iOS version is $3.
Kind of depends on the host. NextCloud does support zero-knowledge E2E encryption. Which is great… though it also supports no encryption, which is not great. How would you tell the difference? No idea. You could look at their website, and hope that they’re not misleading you. Personally I would self-host it. Either on dedicated hardware (like a NAS), or rent server space (which gets real expensive, real fast).
If you want to read up on Nextcloud encryption, go here:
Some instances that host Nextcloud do have E2EE and it’s optional for an instance to do so. The instances that does support E2EE declare them. I believe all of them are paywalled.
MEGA has it’s security issues. ProtonDrive is your best option.
At least they sort of patched it.