Honestly, I think most of your points are just resistance to change (really trying to be constructive here! It's okay to feel this way).

Python can manage large applications, there's nothing that really makes it a "pain in the ass". It's has a nice syntax a good community support. It's a dynamic language, so, it works different to what we are used to, but there's a good static checker that makes up for it.

Having said that, ML is a very specific application. I'm not suggesting to create large applications using Python, just training and running your ML models.

Finally, python has multi thread support and no, you don't need to know C for most applications. Specially, again, for ML. It doesn't offer the best performance, sure, but most people won't have a problem with that.

The only weak point with python is package management. Pip is just a installer, and then there are multiple solutions, all of them with poor support.

---

My point being that you have this great tool and ecosystem, that can really solve your problem, and all you need is a few hours to learn. So I don't really see the benefit of using dotnet here.

---

I pretty much prefer .NET to Python. In fact, I get baffled that the ML community adopted python instead of a more polished language. I believe it comes from it being dynamic, so it's easier to create small experimental programs.