Yes, it does. As long as your custom URL has a domain name and a fitting, publicly trusted (i.e. not self-signed) security certificate for it.
And that certificate has to go into the Plex configuration. https://support.plex.tv/articles/200430283-network/
You can add several adresses for the same server into “Custom server access URLs”.
(just don’t insert a space character after the comma to separate them)
Each server has to have its own URL. And it doesn’t matter much, because the user only needs to open the Plex app.
There is no need to memorize server adresses.
The server is claimed into a plex.tv user account. The above configuration will ensure that plex.tv will store the URLs of each server.
The client is signed into a Plex.tv user account as well. That plex user account will tell the client which URLs are assigned for all servers, to which the user account has been granted access. All libraries from all servers are available at once in the client app.
See Plex for Android doesn't use server's custom access URLs - #8 by RainbowCookie32 for an example.
