Try pulling a broken cartridge out of a 20 year old shower faucet after the handle snaps off. I'll give you the pliers you need. You get one try and if you fail, you will now need the tools to remove tile or cut drywall, cut pipes, solder, etc.
This is one of those things I believe to be more about feel.
That plumber has done this 1000 times and will make it look easy.
They can pass you tools, walk you through it, give you as much help as you can possibly receive, but you'll struggle a ton anyway. Or, as you say, break it.
Practice makes perfect. Sometimes it is still cheaper to get somebody who knows what they're doing. We can't yet remote that in.