I use my German passport to go through Egates at LHR and to use the EU lanes in Europe - now you can throw tomatoes at me
Jokes aside, last time myself and wife (UK passport) travelled to MUC and she was properly interrogated by German Border force. I do normally travel arrangements so she wasn’t clear in which hotel we stay so she called me to come to the check point (I used egates). Just by saying proper ‘servus’ to the border force agent it was proof enough that she’s married to a German and was allowed to pass
Take back control!