Because of how ssh works with cloudflare tunnels (at least as far as I know), anyone who wants to use SSH here needs to install cloudflared and add the following to their ~/.ssh/config in order for Cloudflare Access to allow it through:

# ~/.ssh/config
Host git-ssh.devmarked.win
    ProxyCommand cloudflared access ssh --hostname %h

I haven't found a workaround. Setting the mode to bypass in cloudflare access doesn't remove the need for this.

If you don't want to do that, just use https.