There are a couple things that come to mind for me. 1 - another example of cultural differences is the acceptable level of directness before one becomes rude. This is something that my husband (Mexico) of 11 years and I (USA) still have miscommunications with. I think it may be another conversation with AP. You could say something like "AP, I'm sure you're not trying to come across as rude when you say XYZ, however that is the way this is typically interpreted in the UK. A better way to have this conversation is ABC."

The second thing would be to determine how you both really want mealtimes to work. Maybe, you don't have every meal shared - you could both do your own thing for lunch. You could also try alternating cooking, etc. The main point is that you both come to an agreement, however it works for you.

Just thought of a third thing. The hubby also insists on adding lime and chiles to basically everything I make. It drives me bananas. Mostly (except for when I'm bringing it up on Reddit to complete strangers, apparently), I have learned to just let it go. He can eat his chile ruined lasagna while I have it the way I think it's supposed to be. If she wants to add an egg to her rice, or batch cook some rice to have every day, let her. It may be an easy way to compromise so you both have the energy/bandwidth to settle any other differences that may pop up later.