I checked the docs but not sure how I missed it.
since there is a way to get multiple domains in one swag you can achieve what you were hoping for to host multiple domains on the same host
the principle is simple:
One main swag that will have ports 80/443 ported will manage certificate requests for all domains and subdomains, also host one of the domains and act as a proxy to all other domains.
other containers don’t have to be linuxserver swag can be any other http server, but you need to remember to use different ports for each of the server instance, so for example second http server would have http/https mapped to example 80001/44301 and then you proxy secondary domain from main swag to http://127.0.0.1:80001 and do the same for all further domains
You can also proxy http services from other servers/nodes as well just need to use their IP address instead localhost (127.0.0.1)