As mentioned they are a playground. The Archer C7 are a newer playground. I want to update all my routers and get everything work and then they are exchanged or in case a newer device gets broken, they are a backup device.
Still working on the correct configuration of my wireless bridges.There is something wrong or missing. See How to configure DNS and DHCP with a wireless bridge? - #6 by linuxuser
Probably a few lines only in the config files, but hard to find for me.