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

You can try them both out on https://qlick.cloud

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.