I guess i'm not entirely sure what you're looking for, then.... Once the pod is up and running, directing traffic to it is the same as directing/forward traffic to any pod/service. And that's going to 100% depend on what/where/how you're hosting it. Could be through a different port on your host, could be through a different IP from your subdomain, could be through setting up httpd.conf on a webserver, could be through some kubernetes/load balancer magic, could be through simple configurations on your web hosting provider, etc.

And yeah, if you use the subdomain to hide the redirect, all traffic will go through it. This is a common technique used for 3rd party hosted things on your site, though, like helpdesk stuff. If your web server is correctly configured for HSTS, though, this shouldn't be any issue, since it all goes through https, and should be e2e encrypted.