Eggs are good for breakfast, cooked anyway you enjoy them, even as an omelette. I sometimes enjoy one slice of Nimble toast, with a poached egg on a bed of wilted baby spinach, then have some berries - you can have full fat cream with them if you don't like greek style yoghurt. One of these days I will find time to try making some breakfast egg muffins, they look nice and are low carb/keto, and will keep in the fridge a few days or can be frozen then reheated in microwave. There are lots of low carb and keto ideas on the web for all meals.
Best to avoid white bread, potatoes, white flour, rice, pasta, limit veggies that grown under the ground, tropical fruit (berries are best), cakes, sweets, crisps (my downfall, alas), pastries etc - read the carb contents and go for the lowest - if you spike there are usually alternatives such as cauliflower mash or cauliflower rice, konjac noodles and rice.
I'm not a great one for breakfast, never have been, but I try to eat a little something if I am going out. I'm not on meds though - and everyone has their own routine that suits them best, no one size fits all, so it is always a trial and error to get it right for us as individuals. Do you use an online food diary? I find that is good to *try* and keep me on track with my daily limits of carbs, fat, protein - I don't take much notice of calories but usually keep under it anyway. There are plenty you can use for free, personally I use My Fitness Pal, but there are many others so it may be worth checking a few for one that suits.