It's very different, CF tunnel is a reverse proxy to your service, Tailscale SSH manages authentication to machines inside your VPN. I can't see any resemblance, personally.
First of all, for CF, it manages the authentication part of ssh with SSO support (personally I used github)
Secondly, it has clients (on iOS it is called Cloudflare One) which can act as a VPN service as well. You can access any IP addresses (if you setup the vpc correctly [0]) directly accessible to cloudflared daemons.
