Any guide out there is assuming you’re using a VM and not containers.
Frappe/frappe_docker is the only source for anything related to containers.
Recently I posted somewhere about overriding nginx config using the template. Frappe/erpnext deploy with nomad: proxy/upstream not working - #2 by revant_one.
Check the nginx-entrypoint.sh as it generates the nginx config using the .template file. You can override the template or the file directly.