Los Angeles is a mecca for people with alternative diets (vegetarian! vegan! gluten-free! raw! etc.) and you can find a vegetarian version of almost anything here. It’s usually very easy to find good vegetarian options even at places that don’t specifically cater to vegetarians. Vegetarian versions of dishes I thought I could never eat again are plentiful here, including Vietnamese pho and Japanese ramen.
I know the idea of vegetarian or vegan ramen sounds blasphemous to most ramen purists but when it’s done well, it tastes really good. And in LA, there are a variety of places that serve vegetarian ramen, one of them being Ramen Champ.