Many European countries have secure electronic identifications that are trusted by the government, banks etc.
Linkedin could easily use this to verify the identities.
Example of services where you can verify the identity with 35 different providers using a single API:
https://www.signicat.com/products/identity-proofing/eid-hub or https://www.scrive.com/products/eid-hub
I doubt it would take more than a sprint to integrate with this or other services.
Digital certification from the gov sounds a lot like "digital ID", which has run into considerable resistance in the UK and EU in just the last few months. As a general observation I find most EU citizens I interact with much more trusting of government than ... well, any other group of folks I have interacted with (I have the privilege of having lived and worked in S. America, N. America, sub Saharan Africa and now an EU country). If it does not fly well here, I don't think its general solution that most people would be comfortable with.
https://blogs.lse.ac.uk/europpblog/2025/10/09/britcard-uk-di...
There should be no verification. The idea of a single platform where every worker is listed, identified, and connected to other people he/she knows IRL is scary. It shouldn't exist.