[EthanHeilman]

Given that only key appears to support FIDO2 it seems unlikely that it pre-dates FIDO2.

>"Onlykey supports multiple methods of two-factor authentication including FIDO2 / U2F, Yubikey OTP, TOTP, Challenge-response."

[0x0359463]

It predates FIDO2, the OnlyKey has been around since 2016 and before FIDO2 it supported FIDO U2F.