This is just a Nextcloud rebrand with a confusing domain name. It claims "Core is [100%] Open Source" but no source code is provided beyond what's already available in the upstream projects, and it's unlikely that there will be (as this happens a lot). It's a one-man project without a track record or certifications based out of a shared office space [1].

And don't get me wrong: there's nothing wrong with starting a business rebranding Nextcloud and keeping your development closed source, as long as you're honest about that, which this initiative is not.

If you're looking for a Nextcloud hoster, there's a long list of partners here [2] that have contractually obligated themselves to contribute back to Nextcloud for every user they onboard.

[1] https://blog.tomaszdunia.pl/officeeu-eng/

[2] https://nextcloud.com/partners/