I'm mostly a backend engineer, but I've worked with react and Vue a bit and, back in the day, jquery. React is definitely way harder to grok than the other two - for someone who doesn't work on front-end full time. It feels like a different language of its own, while jquery and Vue seem to complement JS.
TBH that's part of its appeal. JS is a mess, React is a relatively clean tiny little playpen inside a hoarder's house. If you're used to the stacks of newspapers and pizza boxes, it's a shock.
