I would say it's more likely that he is interested in a configuration that is rare enough that no one else is doing the same.
If I am understanding it correctly, he wants to expose the nextcloud service on the IP-address provided to him by PIA.
That sounded interesting, so I researched it a bit/gave it some thought:
It will require that the DDNS configuration points to the PIA IP and not his own.
It will also require that PIA either forwards all incoming connections to to his own IP or at the very least allows him to configure port forwarding of select ports to him, according to the PIA support portal they
support the latter.
It will probably also require some sort of configuration on the pfsense firewall to allow connections via the VPN to go to the nextcloud server (which may require NAT configuration - but I am not sure).