I'm not trying to be one of those guys who tries to tell everybody what to do but I know quite a bit about diet and health.
No fad diets are good in the long run. It doesn't mean you couldn't go on the carnivore diet to achieve a short term goal like lose weight of gain muscle. Same for keto. It's a great way to she'd some pounds for summer but it's not sustainable for the long run.
The best diet is a clean diet with lots of veggies, fruits, and yes meats. Not a big Mac from McDonald's but a nice organic slice of meat. We are designed to eat all that stuff. Again it's not to say you can't be a vegan. Vegan is a very healthy diet but you also have to supplement because the vegan diet doesn't provide you with everything you need. Nothing wrong with experimenting but if your goal is overall health then eat a variety of healthy foods and cut out the garbage and you'll be all good.