From one side yes. From the other side no. Seems our ISP also has this blocked incoming for security reasons. Because they can't be sure their customers configure it the correct way and then it might be abused for DDOS or other kind of attacks. So after years of having it open, they decided to close it.
On the other hand, only very few of our ISP's (rather small ones) would give the service to give you a custom PTR record. Mostly those who do that, also do not have port 53 closed.
I also hope
@Lavien is able to resolve it, otherwise it might be better to use an alternative solution and get a cheap VPS for example with Contabo or another cheap but good VPS provider and run the server from there. More people are doing that.