The strange thing is, that blocking in edge only works, when i enable query logging, set privacy to the highest setting and disable conditional forwarding to my fritzbox.
In the fritzbox i set the pihole to my local dns server.
i already flushed my dns (ipconfig /flushdns)
restarted all devices (router, pi-hole and computer)
There is an open issue with the highest privacy level in Pi-hole V5. When you set this privacy level, your adlists are bypassed. This may not be related to your problem, but be aware of the issue when you select this privacy level.
Since the behavior you see is limited to one browser, it is likely related to a setting on this browser, or perhaps the DNS server in use by the client on which you are running the browser.
Tail the Pi-hole log in real time and see if the browser traffic is reaching Pi-hole. From the command line, the tailed output is color coded to show blocked domains in red.
This maybe just a coincidence: Privacy levels in Pi-hole do not affect blocking at all, they just configure logging.
I do not use MS Edge - did they complete the move to a Chromium engine yet?
If so, your observation may be related to enabling DoH by default, which will bypass Pi-hole, see Chrome 83 ships out with enabled DoH.