learning Perl 6 is a commitment to un-learning Perl because there's no realistic way to keep all the semantic differences straight if you want to go back and forth

By all means, learn a language like Rust. But do you seriously think you would have fewer problems going back and forth between Rust and Perl 5? In my experience, being proficient in any programming language is like being able to ride a bike without your hands on the handlebar. If you don't do that often enough, it becomes hard to get back to it. But after a little practice, it should just be "like riding a bike". Well, at least that's my 2c worth.

Also, Perl 6 has several checks on slipping Perl 5 isms into Perl 6 code, and will tell you what the Perl 6 way of doing it is.