Maybe you could take a zinc supplement. I hear veggies don’t get a lot of zinc.
I personally try to eat alternatives when I can. Not for the animals, but for my health.
Also, I don’t think that erection level is something that can be changed. Sure a low erection level will droop, but I can get a raging hard on and it points maybe 20 degrees from orthogonal max. It’s just the way god made me :)