Breakfast is one of the fastest and easiest things to make!
Lots of fine-cut cereal grains can be prepared into porridge by just pouring boiling water on them.
Consider, for example, "Quick Oats'. But wikipedia has a list of a few hundred different grains you can use to make porridge:
Besides changing the type of grain, top it with fresh fruit, nuts, jam, coconut yogurt, etc..
Add a handful of nuts on-top for protein.
You could buy a boxed cereal and just pour (oat) milk on it.
Add a handful of fruit or berries, if you'd like.
Protip: you don't have to buy boxed cerials. You can make your own muesli or granola, both of which can be very high-protein!
Eat a banana. Or an apple. Or both.
If you want to get fancy, buy a bunch of different fruits. Once a week, cut them all up, put them in 7 jars and store them in your freezer. The night before, just move from freezer to fridge.
Bread & Butter
Put some vegan butter on bread. Or jam, if you want something sweet.
Or dip the bread in olive oil, za'atar, tahini and/or dibs (date syrup) as they do in the middle-east.
For high-protein, spread it with baked beans or marmite (yeast extract) as they do in the UK. Or peanut butter as the do in the US. Or hummus.
Put some (unsalted) nuts and seeds (eg peanuts, sunflour seeds, pumpkins seeds, cashews, almonds, walnuts etc) and dried fruit (eg raisins, banana chips, cranberries, dates, apricots, etc) in a bag.
A few handfuls makes a great, fast, high-protein breakfast.