European digital infrastructure consortia are as of #2022/12/14 a new legal entity. Decision (EU) 2022/2481 of 14 December 2022 establishing the Digital Decade Policy Programme 2030

Requirement is that Member States may implement a multi-country project by means of an EDIC. The EC will than create them as legal entity by the act of an EC decision on the consortium funding. There is a public register for them.

No mention of UBO (although if members are publshed, those members will have UBO registered).