I’m actually behind 3 routers and still hosting stuff to the internet. My house is behind cgnat, I have two isp routers, which both connect to a pfsense router (ip of which is in tge dmz of each isp router).

My pfsense router and a free vps hosted at oracle are both connected via tailscale. Pfsense router advertises specific subnet addresses to the tailnet. VPS uses caddy to reverse proxy to those subnet addresses to expose them to the internet.