> Having one login for all government services would massively improve the efficiency

I'm quite surprised that's not a thing over there

In Poland you can log in into governmental services platform by: scanning QR code with a digital id app (requires authorizing it beforehand but once it's done it works like a charm), a separated national id card app - only for newer documents with rfid chip, 3rd-party login via bank (as long you pick bank that offers it - some smaller ones don't), a qualified digital certificate within yet another app. There should be another option for EU citizens who in theory would use their national SSO platform as a provider but seems it doesn't work right now.

That digital id app will likely integrate everything else since it already provides a way to secure your national id number (a SSN equivalent) and driving license, health services (doubling the functionality) and train tickets components.

A separated health service app is also available where you can manage prescriptions for medicines, referrals for tests and vaccinations.