I applaude you for keeping things simple, not over-engineering, and resisting the urge to use the latest tech.
They are using React, Tailwind, Typescript, Docker, FP etc. which is what you would find in many modern tech stacks.
That's what I love about this "we should only use old tech" argument. There is no specifics, justification or technical basis for any of it.
So you end up wondering how old should my choices be in order to satisfy the crowd.
I’m in the same boat as previous commenter - React et al feels like new tech to me.
But that’s because I’m an old fart who’s been using php for over 20 years.
My point is that what often gets criticised as "new tech" is actually quite old. Hence the stupidity of that argument.