Is it fair to assume you are confident carb counting and adjusting your insulin doses?
There have been several threads around lunches over time, so a quick search could return a few ideas whilst folks see your thread.
In the ast when folks have posed similar queries, along the way, they've usually been asked if they have facilities to heat things, refrigeration and if the food must be finger food, or can go in a dish. Sometimes, for those doing jobs involving dirty hands, some have even looked for specifics for not finger food, or food on the move.
Is there any more context you could help us with?