What’s your point exactly? Besides telling me I shouldn’t use AVM hardware?

I’m not using AVM products, as they don’t fit my requirements (e.g. network segregation). Ubiquiti makes decent prosumer hardware with their Unifi line and I’m quite happy with their offerings.

An AVM user asked for potential use cases that FritzBoxes aren’t covering and I provided one.

network segregation. setting up vnets and rulesets for guests, iot or dmz and deploy them site-wide to all switches.