If you want Python just use modern laptop, no need to retro anything.
BASIC has command-like statements, no complexity like lambda, classes, modules, etc.
Just not having line numbers cooked in is a total game changer.
And no GOTO.
If they upgraded the C64's BASIC to 7.0, that would already make a lot of things much more accessible.
Yup, even for the old 8-bit computers FORTH would've been a lot more elegant than BASIC. But back in the day BASIC came with highly valued conveniences such as a soft-float implementation that meant support for the "desk calculator" use case was available out of the box, and users could just go on from there.
No idea what this BASIC looks like though; the documentation seems chaotic and hard to access. Just saying that BASIC does not necessarily mean the BASIC that you or I used back in the day. I also agree that you can do a hell of a lot better than Python to introduce programming to kids.
Important thing about BASIC is that each "command" does a rather limited amount of "stuff". In that way it is kinda similar to assembly language.
As an adult I'd strongly prefer Lisp over Basic. But I appreciate Lisp or lambda calculus elegance after I spent some time with more basic kind of stuff. Going to higher abstractions right away won't have the same effect
It encourages the user to learning programming and develop their own apps.