true that, perl5 to perl6 (now raku) was a master class in that

Raku is the most modern PL s metric

I stopped using Perl in the early 00s but I've heard rumours, how bad was it?

well it started out with perl6 as a breaking change major upgrade to perl5

the perl community fractured into those that wanted to avoid a breaking change (since they feared the kind of pain that Python 2 => 3 would later encounter) and those that wanted to evolve the language with things like a Type system and Object Oriented coding as standard

the fracture became a chasm when it became obvious that perl6 was taking years and that there was no migration path from perl5 to perl6 - users began to explore options and often Python was top of the list

this was exacerbated by the use of perl6 as the name ... later (much later) the name was changed to raku ... but by then the perl language was a shadow of its once dominant self and CPAN (the perl module library) lost a lot of folks doing maintenance and improvements so that began to bitrot

fear lead to anger, anger lead to hate

[btw raku is now very nice with all these features and still the great feel of classic perl and has a small but active and friendly community]

Is there a canonical "perl 6" now? LIke I can't go to perl.org and download one, or at least the "latest stable version" is listed in the 5.x range still.

Or is "perl 6" not even a thing to ask about, and "raku" is what was to be "perl 6" became?

afaiui the perl folks are targeting perl7 as the next major release to avoid confusion (but suggest you ask them)

if you want raku, then you can install from rakudo.org or rakubrew.org