My approach with hiring is to try and find solid JavaScript programmers foremost. People with experience in the tech we use, or people with a lot of experience with other languages are nice to haves.
Anyone who has a solid grasp of (modern) JavaScript will be fine with any front end tech stack.
Well, I mean, sure... but, having hired all these random "solid JavaScript programmers", what do I tell them to use and/or learn? To do useful work, they all need to be using the same thing—so... how do I figure out what should be the standard for a project, if there's nothing forcing any particular option?
You can let them decide? Then follow agile principles to make sure they are delivering prototypes/features.
Ideally you would get a grasp of what they need to do and some idea on how they need to do it. If you don't then you should hire someone that does, or who you can feel almost absolute confidence in. Then let them do the hiring.
Anyone who has a solid grasp of (modern) JavaScript will be fine with any front end tech stack.