To enable the Cloudflare Zero Trust web based SSH on an Ubuntu Server 22.04 system I did the following.

• Followed the following directions at https://developers.cloudflare.com/cloudflare-one/tutorials/ssh-browser/
• Added an SSH config file /etc/ssh/sshd_config.d/cloudflare_zerotrust.conf, shown below
• Restarted SSH with systemctl restart sshd
• Used sshd -T to verify that ssh-rsa is now listed in the running config

cloudflare_zerotrust.conf

PubkeyAuthentication yes
PubkeyAcceptedKeyTypes=+ssh-rsa
HostKeyAlgorithms=+ssh-rsa

Without both the key type and key algorithm allowing ssh-rsa I was unable to successfully connect.