What can I put on my bread instead of eggs or tuna if I want to get a lot of protein from plant based products?

II don't know exactly but you could try searching on Google high protein breakfast and I'm sure you'll get very delicious options. Sorry I cannot help more and good luck 😊

Hummus! Peanut butter! Any bean-based spread. I personally use black bean paste and some sunflower seeds on top. Just cook the beans and process them into a paste with a pinch of salt.

Houmous, peanut-butter (better with no sugar in it), avocado (+tomatoes, that's delicious). banana.
Also you may add to all of this some seeds (pumpkin, beniseed, ect.) and drink some soya milk.

Nut or seed butter, hummus, you could make a veggie sandwich with kale and spinach and other vegetables. Veggie burger or black bean burger might be enjoyable.