What exactly makes JavaScript so unsuitable?
If you look at JavaScript's history (especially for backend development), it reads like a series of accidents: First, the JS language was hacked together at Netscape in the space of a few months in 1995, and after that it was quickly baked in into all web browsers and therefore became very hard to change in a meaningful way. Then, Google developed the V8 engine for Chrome, and someone thought it would be a great idea to use it for running JS in the backend. My thoughts on that were always: "just because you can do something doesn't mean that you should"...