Perl (talking about Perl 5, don't know anything about Raku, don't want to know anything about Raku) simply treats strings as sequences of numbers without requiring numbers to be in the 8-bit range. This makes it easy to say that those numbers could in principle be Unicode codepoints. The problem is that the actual assumptions about what those numbers represent are implicit in programmers' minds, and not explicit in the language, much less enforced in any way. The assumptions shift as strings are passed between different libraries, and sometimes different programmers working on the same codebases have different ideas. Perl will happily do things like encode an already-encoded string, or decode an already-decoded string, or concatenate an encoded string with an unencoded string, or reverse a utf-8 string by reversing the encoded byte sequence, etc. etc. So it's easier in Perl than in any other language I've ever used to end up with byte salad.

It'll take you, let's say, the first few years of your Perl career, involving painstaking testing of everything you do with nontrivial characters, to truly grok all of that. But the problem is: You're not alone in the world. If you work on a nontrivially-sized project in the real world that heavily utilizes Perl, then byte-salad will be what you will get as input. And byte-salad will be what you will produce as output. It is frustrating as hell.

Unicode was a pretty painful matter in the transition from Python 2 to Python 3, but Python's approach means that the Python ecosystem is now pretty usable with Unicode. This is not the case with Perl at all.

    foo.sort    { |a,b| a.expensive <=> b.expensive } # basic
    foo.sort_by { |a,b| a.expensive <=> b.expensive } # Schwartz-enabled