Using DDNS or Dynamic DNS is a good solution when dealing with frequent changes in your Public IP address. With this, you can always reach you network using your hostname and the DDNS service will automatically update the DNS records with the IP address. You may want to consider the below setup when dealing with this kind of situation.

1. Sign up for a DDNS services like No-IP, DynDNS, or the likes. They usually have prepaid or postpaid plans.  You might need to follow their instructions like create a hostname and setup your DDNS client on your network to update the IP address with the DDNS service every time there's changes in the IP address.
2. Configure the DNAT rule in your router or firewall using the hostname instead of specific IP address. Steps may vary depending on the specific brand, model, and firmware version of your router or firewall device. Specify the hostname as the destination for your DNAT rule instead of specifying a fixed public IP address.
3. Testing and monitoring

Using DDNS or Dynamic DNS is a good solution when dealing with frequent changes in your Public IP address. With this, you can always reach you network using your hostname and the DDNS service will automatically update the DNS records with the IP address. You may want to consider the below setup when dealing with this kind of situation.

1. Sign up for a DDNS services like No-IP, DynDNS, or the likes. They usually have prepaid or postpaid plans.  You might need to follow their instructions like create a hostname and setup your DDNS client on your network to update the IP address with the DDNS service every time there's changes in the IP address.
2. Configure the DNAT rule in your router or firewall using the hostname instead of specific IP address. Steps may vary depending on the specific brand, model, and firmware version of your router or firewall device. Specify the hostname as the destination for your DNAT rule instead of specifying a fixed public IP address.
3. Testing and monitoring