You do not even need a port based firewall when the server is open on the internet.
When you configure the software to not have unnecessary open ports over the internet connected interface then a port based firewall is providing zero additional security.
A port based firewall has the benefit that you can lock everything down to the few ports you actually need, and do not have to worry about misconfigured software.
For example, something like docker circumvents ufw anyway. And i know ppl that had open ports even tho they had ufw running.
You do not even need a port based firewall when the server is open on the internet.
When you configure the software to not have unnecessary open ports over the internet connected interface then a port based firewall is providing zero additional security.
A port based firewall has the benefit that you can lock everything down to the few ports you actually need, and do not have to worry about misconfigured software.
For example, something like docker circumvents ufw anyway. And i know ppl that had open ports even tho they had ufw running.