Duckdns no access but off-site notifications work

First of all I looked in the forum to see if there are similar cases but haven’t found them as of yet

Problem;
Can’t access my homeassistent (running x86 version) via duckdns externally, anymore. (Locally works like a charm via browser using IP)
But notifications from automations I still receive when I’m outside of my home network

The moment I could access my setup anymore was some water damages on my previous homeassistent server and network devices
After some drying only the motherboard was broken
But the nvme drive, my Modem-Router and router booted again, where the nvme drive I of course had put it in a different pc to test

The routers did a reset after the initial bad boot
But I reinstalled everything as it was regarding port forwarding
But unfortunately I can’t access my duckdns addres
And get a time-out error (using Chrome on Android or Windows with hotspot)and in my companion app the error is timeout
But the strangest thing is that I receive notifications from my setup although I’m not connected to my local network
From both old automations as from new ones which I created later for testing purposes

I’ve removed/cleaned cache, removed the companion app and reinstalled it (with the duckdns external link)

Homeassistent runs
Duckdns
2FA
Adguard installed but disabled
Router has dns of ISP and also tested with 4.4.4.4 and 8.8.8.8

Network is
Internet → Modem-Router → router → switch → homeassistent server (all wired)