I'm not familiar with all current ongoing projects. Because of the situation mentioned above.

Currently I'm involved in projects surrounding https://developer.overheid.nl/kennisbank/security/standaarde... . Have a look there. It's not FLOSS in the way that you can just provide PRs of things you'd like different, but FLOSS in the way that you can get in touch and with enough expertise, have people listen to you.

Upvote for wanting to help with digital soverign effort (UK national here).