There are no clear examples of how an Attestation statement can be verified on C# locally.
Spent sometime to get it working.

var decryptionKey = Convert.FromBase64String("<DECRYPTION KEY");
var verificationKey = Convert.FromBase64String("<VERIFICATION KEY");
var signedAttestationStatement = "<ATTESTATION STATEMENT";

var ecDsa = ECDsa.Create();
ecDsa.ImportSubjectPublicKeyInfo(new ReadOnlySpan<byte(verificationKey), out _);

var decrypted = Jose.JWT.Decode(signedAttestationStatement, decryptionKey);
var payload = Jose.JWT.Decode(decrypted, ecDsa);