I'm not saying it's at the same time. And yes, type feedback is mostly instant.
The code base I'm currently working on takes a long time to compile and sometimes there are errors. Or there are runtime errors. Combined with the much higher volume of code I have to write, and the greatly reduced readability C# does feel a lot less productive than Python.
Usually when I see that, it's because someone's implemented an inappropriate pattern, or gone over board on 'SOLID' principles or whatever.
C# developers seem especially prone to getting trapped in stupid implementations that massively bloat the code. For taking some Uncle Bob dictat to an unnecessary extreme, or implementing a dangerous pattern like CRQS stupidly for a simple CRUD app. Less a reflection on the language and more of a reflection of the enterprisey culture.
I was interviewing in the C# world recently, it was quite disheartening to hear the same phrases repeated 'hybrid microservices' (i.e. we've got the worst of both worlds in one project! But our TA got to put microservices on his CV!) or 'we value SOLID code' (i.e. we've massively over-engineered our code, development has slowed to a crawl, there are far too many interfaces, and debugging is a nightmare!).
But you can write great, terse, code in C#, and I feel much quicker than dynamically typed languages. I feel like I can implement the same code much faster in C# than I do in the equivalent javascript, even though I've been writing javascript for longer, and that's down to the autocompletion and snippets of a powerful IDE, which dynamic languages will never be able to match. It's also much easier and quicker to move code, refactor, and generally redesign your code on the fly as you're exploring the problem space.
Even Javascript has quite a bit of autocompletion nowadays, with all the annotations coming from typescript. Much less typescript itself. Frameworks on the JS side also massively improved.
Same thing with Python. Not that it really needed annotation much, the productivity always was quite high, whatever people not using Python said. Now there is static type checking and the IDEs got even smarter. In my experience even statically typed software still needs automated and manual testing so much of the benefits are limited.
The code base I'm currently working on takes a long time to compile and sometimes there are errors. Or there are runtime errors. Combined with the much higher volume of code I have to write, and the greatly reduced readability C# does feel a lot less productive than Python.