So looking at the UK gov dive into this (basically I think a good and necessary step forward but the devil is in detail)

https://assets.publishing.service.gov.uk/media/69b2bd51c8010d37b34e008a/Making_public_services_work_for_you_with_your_digital_identity_2026.pdf

I think better with real examples - and was wondering if any countries have already done this, and if anything is FOSS?

EU architecture and implementation (including code) here: https://github.com/eu-digital-identity-wallet

I have no trouble using my CAC with Debian using only FOSS.