How do I replace this water supply handle?

What would be the simplest way to replace it? I just want to replace the one handle since it snapped when I shut it off to replace the faucet. 🙃

Can I cut it off below the current handle, use a Pcb to pex adapter and find a new handle? Or would replacing the entire line with pex all at once be best? Thoughts?

I can live without it for a while so I’m not in a hurry to get it done. It’s in the bathroom and broke off in the off position. I just want to make the best decision when I do something about a replacement.

I know pcb is bad and hasn’t been used in ages, but I inherited this place and the list of things that need replacing is mind boggling.

All the lines need to be replaced throughout the house and I’m looking into how to update them and bring everything up to code. For now…. Just the handle.