@TaxDan Nice move :)
For editing docs online, I know Collabora and OnlyOffice; both of them can be installed in Nextcloud, which would give you the "drive" replacement.
I know you can get free Nexcloud accounts at several providers (check their page), but you know, if you really want privacy, self-hosting would be better.
If that is not an option, I know there are apps that let you encrypt the documents before sending them to your Nextcloud account.