The only non-meat “hamburger” I’ve ever had that tasted good had a large grilled shiitake mushroom cap instead of beef.
I had a friend that was a vegetarian and when we did cook outs a shiitake mushroom cap is what he would eat...he thought it was crazy vegetarians trying to get people to eat vegetarian with foods that try and mimic the taste of meat. He said the best vegetarian food was that witch didn’t try to mimic the taste of meat protein but instead went with the strength of its own tastes