Assign URL to homelab using Cloudflare domain

[arnob216]

I have a domain which is recorded under cloudflare for DNS. My home network has dynamic IP. In that case, how can I assign meaningful URL such as immich.local.mydomain.com (2 layer of subdomain). I do not want to use internal DNS resolver like pihole.

I tried using NGINX but could not make connection to immich server using above IP. What am I doing wrong.