That sounds like what your wiki page about php-scl was indicating.
Whether it’s the default or not, anything under a given FQDN would be in a single virtualhost, no?
That’s a bit of a step backward from SME in terms of functionality, then–particularly since I chould chose different php-scl versions for each ibay, while I don’t see that I have the ability to do that for subdirectories of /var/www/html. But if that’s the way it needs to be, I can make it work.
One issue with using the virtual host is that, in addition to updating DNS, I also need to remember to update the Let’s Encrypt certificate–Neth isn’t yet quite smart enough to track all its configured FQDNs and automatically put them all on the cert.