The status is that engeneers found the issue and provided me the fixed firmware for a test. The connection to ISP (vodafone de) is working and wifi also is good, there is only issue via LAN...

yeah, there is support email 2 hours ago, thanks!

yeah, there is support email 2 hours ago, thanks!

This screenshot where my router just connected to another router. I wanted to show Menu of settings that I was talking about

@Kevin_Z Vodafone is not required PPPOE in ipv6, but I have to put my credentials somewhere, right? Since I choose DS-lite I can't choose PPPOE in Internet Settings. Where should I put my credentials...

I used this AFTR name but "ds-lite" option didn't come up in ipv6 menu. I attached fritzbox log, which is succesfully connected to Vodafone