@reneaz You could try incorporating digestive enzymes like amylase, protease, lipase, cellulase, and alpha-galactosidase, which help with the digestion of legumes.
This might make it easier for you to include legumes in your diet.
Additionally, you could try protein sources like quinoa, nuts, seeds, edamame, and nutritional yeast.
Protein shakes or bars can also be a convenient way to supplement your intake without relying solely on tofu and seitan.