You think clients care?
Likewise I think someone starting up for themselves is more likely to be a React programmer than a PHP programmer.
I also think it's damned near impossible to find React developers who are capable of doing anything that isn't React flavored.
For those reasons alone, I'd choose PHP over React, especially if I want to scale.
As someone who ran a company for 5+ years on a Node.js stack, never again.
Before when I managed 5k+ servers running PHP, I actually slept at night knowing nothing was suddenly going to go wrong because of some stupid memory consumption bug or exploit in a popular and critical package.