GL-MV1000 Brume without routing

Thank you very much for your help.
I think you have understood my question correctly.
By the sentence:

I meant that I set my home router to 192.168.1.1 and the Brume to 192.168.1.222.

But anyway, I have now followed your instructions.
But I didn’t have to click “Apply & Save” under LUCI but “Apply Unchecked”. Otherwise the Brume hangs up.
Now everything is set up as you described (LAN-IP, DHCP, Gateway, LAN-LAN connection).

But now I see in the Admin Panel of the Brume that there is no Internet (“No cable detected in WAN. Please plug in an Internet cable”). VPN does not work either.
I have checked all settings again, but can’t find the error.
Do you have another idea ?
Thanks.