Attestation of what? It's none of your business how I secure and configure my phone. I use a smart card on my Librem 5 btw. See also: https://news.ycombinator.com/item?id=47647047
Configure your phone however you want, then use your physical ID because your phone isn't supported. They're not taking it away. In the same way that you can file your taxes. Having an online filing service doesn't mean you're being "excluded" because your i386 running BeOS isn't part of the supported hardware. Send a letter. It'll still work.