Understood ; I run all my services on different Proxmox VMs/containers... this isn't usually an issue until two needed the same 80/443 ports... I suppose I could change the ports for my Bitwarden, as I'm the only user connecting [aside from a partner or 2...] and I could modify the links used to connect accordingly.
I feel like I'm missing some EASY thing; like can't my apache2 just route the bitwarden.domain1.com traffic to another local IP address...
All these replies are helping - I just gotta pick the solution and GO; just trying to find the easiest, best solution.. :P