Port Forwarding on PostgreSQL Databases

Besides the obvious and serious security risk, it is not advised to manage individual Ips via hba.conf.

Strongly recommend a per-customer VPN solution that includes a firewall. Every remote user connects through the VPN. PostgreSQL sees stable VPN addresses.  Then you can use something like: 
hostssl   all   all   10.88.0.0/24   scram-sha-256

Note:  This setup is outside the scope of our ability to support your PostgreSQL database.  You will have to support your own database in the event of a incident.