I know its intimidating but getting a managed instance of nextcloud somewhere like Hetzner is really straight forward. You wont have to do much if any admin past the initial setup.

But services like Proton are a Swiss alternative to a lot of these cloud services.

You don't need to selfhost.

Here is one place where they'll do the hosting for you, and you just use it.

https://www.hetzner.com/storage/storage-share