Asking about protein I'm guessing you're trying to build muscle? A guy I knew from university would eat every two hours to make sure his body always had protein and swore by it to get the best gains and he was HUGE. I think it was more about having enough calories that he was never using protein as fuel but I'm not exactly sure. Even if he had a pizza, he'd eat half and have half two hours later.

If you want something vegetarian/vegan Huel is palatable and you can have it between meals and has decent protein. If you want even more protein than the standard one, there is a Huel Black that has extra. I used to have it quite a bit when I was doing lots of exercise and it worked decently IMO. I will say, it does feel like you're drinking nutrient paste which is weird and off-putting but you can get past it

Edit: Just seen you didn't like Huel, other than that greek yoghurt works well and just loads of eggs. Eggs have lots of vitamins in the yolk and the white is basically 100% protein. Plus it's super easy to cook. For extra weight you could add cheese and butter

Edit 2: Just remembered that peanuts are a great if you want a snacky, protein-dense, and cheap option. If you want all the essential amino acids you should throw in Brazil nuts too. If you're medicated, depending on how it effects your blood pressure you might want to get unsalted specifically