> but definitely start with one and stick with it for a bit

Devs are paid quite a bit of money to play russian roulette with their tool choices.

Frameworks are an abstraction and not really key to understanding anything. And devs need to understand, at least conceptually what the framework is doing (or attempting to do) without too much magical BS. Ideally that starts with working with the dom and seeing first-hand the pains and joys of adding and removing elements, functions, sync and async behaviours, data handling, objects etc.

Then only will frameworks click and make sense, and so choose the right tool for the right job.