A lot of what I read suggests taking a vitamin B12 supplement if you’ve stopped eating meat.
Beyond that, most foods – even veggies – have protein. Beans typically top the list, of course. Rice also has protein, even kale and mushrooms have protein. Potatoes have protein and are also good sources of potassium. Corn, peas, and broccoli have protein. Have you ever tried succotash (cooked corn and lima beans)?
Soy beans are packed with protein, but much of what I’m reading suggests choosing fermented soy like natto or tempeh.