python is slow because the extreme flexibility of the language makes it very difficult for compilers/interpreters to perform analysis that could allow optimisations

this doesn't have anything to do with the syntax. we could completely replace python syntax with e.g. pyc bytecode or serialised AST data but the language would still be challenging to execute efficiently as the language is still exactly the same

one can get a few ideas of how python could perhaps be made faster by reading about all the restrictions that rpython imposes

https://rpython.readthedocs.io/en/latest/rpython.html

Ah, I didn't notice that detail of the discussion, thanks.

If "basically python" means "scripting language" vs "C++" then I can see why by that standard "performance" could be a concern to someone.

But, yeah, doesn't seem to be a Python/GDScript specific concern.