A lot of meal prepping and nutrition has to to with circumstances and working effectively around your day. Not much point in preparing frozen soup portions if you can’t reheat them at work for example. Time also a big factor within the working day.
Nut butters are an obvious high calorie, high protein option. Get back on the peanut butter sandwiches (or on crumpets, thank me later) and stop buying Doritos!
Batch cooking chicken breast is a great option and I have that for lunches most of the working week.
Tuna, sweetcorn and lighter mayo is a decent option too for sandwich and potato filling.
with that you can put into fridge day before let it defrost , just have to plan ahead