Yeah moving from python to node for concurrency is insane.

Moving from Python to Node for per-process fully-fleshed out async and share-nothing concurrency however is perfectly sane.

Using any of them for backend is insane, but what do I know, I have to suck it up and use Next.js for some SaaS extension SDKs, while I would rather be using JVM, CLR, or even Go with its spartan design.

JS haters could stand to understand the language has strengths even if it has well known warts.

That's the main reason to move. Same reason people moved from Java to Kotlin, except that might change now with vthreads.