This has been an open question since 2017 with no update since: https://www.digitalocean.com/community/questions/any-plans-to-support-u2f-fido-for-2factor-authenication-yubikey-other-tokens

Any update on this? Not just as 2fa for login, but would also be nice if digitalocean started supporting sk-ecdsa-sha2-nistp256@openssh.com keys for droplet authentication, which is supported by openssh version 8+