In true JavaScript fashion, I decided to learn PHP again by building a framework to put all the pieces together in my brain.
I absolutely love Hono.dev, and decided to base the PHP framework on that. Dumbo isn't intended to compete with Laravel, Symphony or Slim, if anything, it's something people can use in production, but also contribute to and be used as a learning resource for others.
There is Unicode support
There is a proposal for generics https://wiki.php.net/rfc/generics
For me personally its not a deal-breaker, there are workarounds if needed.
but for your question, why not?
It's so frustrating to see people just suggesting the "Mainstream" without considering if OP even asked.
Edit : Unicode support is not native. So concede this one, but again not a deal breaker as a language IMO.
There is some very impressive work going on to define how Generics will work in PHP. It’s a matter of when not if Generics come to PHP. I‘m expecting a new RFC for Generics to be created some point next year.