You can for example install nextcloud or seafile on a hosted vps at https://qlick.cloud

or if you don´t want to host it yourself: https://qlick.cloud and use Nextcloud which comes with Collabora Online installed.

€ 15 a month for 8Gb memory, 200Gb ssd server. You can install more apps if you want

Hi! Other option is to use a managed hosting solution for nextcloud. I’m using https://qlick.cloud for that

First of all I’m all in for privacy but in this case they keep your key private. Only YOU can leak your personalized content with your private key. So I don’t see what they would be doing wrong.