Well my Problem was that the firewall rules that i created in my mikrotik Router had to Pointe to my Servers ip. But because the the suffix changed all the time i had to update the rule everyday.
So i created a Adress list that Pointes to my Domain which i Update to my Servers ip with a ddns docker. Now i can use that ip Adress list for my firewall rules.
Its pretty specific to my usecase so it probebly wont help you