Workers and underlying certificate client auth

When using mTLS, workers expose the following fields regarding a client certificate: certSubjectDN, certIssuerDNRFC2253, certSubjectDNRFC2253, certIssuerDNLegacy, certSubjectDNLegacy, certSerial, certIssuerSerial, certSKI, certIssuerSKI, certFingerprintSHA1, certFingerprintSHA256, certNotBefore, certNotAfter, certPresented, certVerified, certRevoked, certIssuerDN.

I’m looking into assessing additional fields, namely algorithm used for sign (signalg) and key (keyalg) and key size (keysize).
Is there any way to do that? Perhaps by acessing the full X.509 cert directly?