A GUI frontend for iptables, but not the Web, and able to see ALREADY existing rules?

Question

linux

It is the GUI frontend that is needed. Not through the Web. (After all, it's not a fact that I have a static IP, a suitable browser at hand, that I want to deploy Apache for the firewall settings, etc.)
I tried Gufw. I'm launching. Shows an empty list of rules. But, "you deigned to lie, mon cher - you are a sodomite and a hypocrite" - there are rules in iptables, and not only "default" ones. That is, we need a front-end specifically for iptables, and not for ufw, which, apparently, is some kind of left-handed utility that does not depend on existing rules, which is never good in such cases.
And one more requirement - sometimes you have to watch / edit iptables not on the machine itself, but in all sorts of Docker containers and other virtual machines where you can’t put DE.
It is desirable to skillfully work with them (or just the ability to add custom strings to all iptables calls - before and after them).
PS I am a developer. I can work with the console. But I love the GUI, plus there are things that are still overkill for me, these include sed (but it is simply replaced by the same Leafpad, or nano if you still need a console) and this same iptables .
UPD : I watched fwbuilder. I found it too confusing - something needs to be created, etc. Even the list of rules is not easy to see.