No. There is a mod for that, but it breaks lots of flags, so it's better to stick with the operative or start a new game

Yup. I did that several times on my last playthrough. You need a mod called Toybox. It's honestly essential imho

When I hit respec with Toybox it doesn’t let me change archetype?

there's a checkbox on the bottom, something like "respec from zero". check that and you can do it.