I used to obsess over the right onion but now I just get whatever and hardly could taste much differences. Everything works, especially if you're a amateur cook.
I have to at least soak them in cold water for a bit before adding to a salad. Otherwise the entire salad just tastes like onion punching me in the mouth.
I was given false information when I was young that, a shallot was a cross between a garlic and an onion. It's not its its own variety within the allium family.
I like to keep a few around fir when I want onion flavor but don't want to cut into a whole onion.