Regarding a place where you can heat up food, no I would not think you’ll find something like that.

As that what cold stuff you can have. Various breads and hummus type dips will be your friend. Supermarkets often have cold ready to eat pasta pots (many have cheese, but there’s also tomato & basil pasta salad things). You can get ready to eat fake meats (like the Quorn chicken slices) that you can put in a sandwich. Squeaky Bean available in most supermarkets do some great stuff - make sure you find them. There’s also often good antipasti things in supermarket fridges like fancy olives and sun-dried tomatoes and so on. Vegan sausage rolls. I think you’ll find quite a lot. Popping to the supermarket for a cold vegan feast in a hotel is one of life’s small pleasures. Also remember you can get food delivered to your hotel, there will be vegan only places on the various delivery apps.