Yes but you can get two free instances under the same account.

Actually you can get 2 IPs for free. Then use high availability

I use ZeroTier on a MikroTik router.

Then just advertise routes on the router.

Ionos.de has a €1 a month VPS

I think 1 core, 1gb ram, and 10gb.

Use either caddy or Nginx proxy manager. Both are easy to setup. Also both are dockerized.

I use Tailscale as my tunnel.

Total latency is about 70-90ms for me.