Yet in principle Cloudron presents a lot of what this initiative is about and there is a lot of Cloudron apps supporting this (Nextcloud, CryptoPad, Mastodon etc...) already.

So maybe this is of interest/there is still some time to add Cloudron's name to this list:
https://eurostack.eu/250-signatories/

In turn, there is a published "EuroStack" Directory to European Cloud, Open Source, and Interoperable Digital Solutions:
https://euro-stack.com/