This solution is not working now

You overwrite $return on every single line, so they could all be false except for the last call and it would return true. Right?

Yes! but the conversion is easy and short, so... why not? xD Regards!

array_count_values() was my first pick, too, but then I realized, that PHP only allows strings or integers as array keys. That's why this weird string conversion has to happen.

Mmm, put this in a line -> $n = str_split(strval($n));rsort($n);
Just for make fewer lines of code, is bad practice...