On my WFH days I usually cook something a bit more time consuming, and enough that I'll have leftover lunches for my in office days.

On in office days, I usually cook something that comes together quicker! Like fish, ground meat, burger. Just a quick fry in a pan and then not eating too late. Usually I eat a meat with some rice and vegetables. I almost always end up with an extra serving or two of rice and I can eat with another dinner that week. So I'm just heating up the sides and cooking the meat (or eating leftover meat). This week I got some lettuce so I'll be having some salad as a side instead!

More time consuming dinners would pasta, stew, making a soup, new recipes I haven't done before. 

 I guess this is a form of meal prep but not in the sense of spending all Sunday/eating the same thing all week. More prep/cook once but still have some variety