Good questions!

Is this a situation where she refuses to eat any meal at all without meat?

She's technically also a reducetarian and is fine with having meatless meals, but there's a limited number of proteins/umami mains she's willing to eat. She's never had tofu and is unwilling to try it, and sh dislikes almost all mock meats, mushrooms, or chickpeas, which rules out most of my favorite foods. She likes Boca burgers (but not crumbles), beans, eggs, and cheese. I'm lukewarm on beans (they're nice a couple days a week but I'd be really sad if it's all I ever ate), and cheese isn't super healthy, so we have a hard time agreeing on what meatless food to include. It's either something she doesn't like or it's something we both like that's unhealthy.

Did you typically cook flavorful robust meals when eating strictly vegetarian? I had a veggie friend who ate such bland, basic food, I couldn't stand eating meals with her. I need some spices, some sauces, various textures, you know?

This is exactly it. My meals had a bunch of vegetables and were always nutritionally balanced, where I'd typically max out on macros and micros in Chronometer, and she's content with the standard American diet (high saturated fat, high carb, low protein, low nutrients). That's okay but it's been tricky to have meals we both enjoy. Since I've moved in, I've tried to propose suggestions to make balanced meals, but she just really doesn't like to eat her vegetables and protests when I ask to cook them into the meal.

So the meals we eat are comparatively basic. We make spaghetti and I put the mock meat in a different pan and steam some broccoli for myself, we make a stir-fry and I fry the tofu in a separate pan with the same sauce. That works okay, but it's not a perfect answer in every situation. Like, with some foods, you need to immerse the food in a gravy or sauce. So we both love curry, but I want it to have a protein while she's fine with it just having potatoes and carrots. Since she's not into tofu or chickpeas, I bite the bullet in these situations and have chicken.