I will confess that I found Mathematica kind of neat back in the day. I never got as good with it as peers did. I'm curious if that would be different for me today.
VS code notebooks also support LSPs with refactoring, typing etc. Black is supported. Step by step debugging is supported. Venv is built in.
There are so many conveniennces in VS Code that whenever I have to use Jupyter Lab I feel a lot of stuff is missing.
My only complaint is how white space heavy the VSCode layout is by default. Probably can be customized, but I have never dug into it.
Notebooks are usually not inherently slow — I use Jupyter in VS Code running off a remote server and it’s snappy.
I have a MacBook Pro 2020.