I've recently built something similar [0], but the complete opposite. I wanted to forward traffic onto my homeserver without a public IPv4. I've tried Tailscale Funnel, but the inability to use custom domains made me look for other solutions. I ended up with a fly.io app acting as a TCP proxy over Tailscale. Considering how crappy the setup is, it's surprisingly reliable. Great job fly.io and Tailscale teams! I haven't had any issues in the month or so I've been using it.