As for performance well the GDExtension support has also gotten much better. You can always go down to C++, Rust, Nim, Zig or whatever. It is really easy to set up.
You can also use other garbage collected languages. I once tried the Lua bindings and they worked fine.
The problem with C# is that its garbadge collection is not really suited for game dev. The creator of the Mono runtime actually calls using C# his Multi-million dollar mistake and instead works on swift bindings for Godot: https://www.youtube.com/watch?v=tzt36EGKEZo
But if you really love C# nothing is stopping you. I prefer GDScript.
Swift might be cool too, I've only used it a bit but I liked what I saw.
(yeah there are escape hatches, but it's weird to use them)
So when people come out and defend gdscript for being not that bad, it's like, okay, but it's still really shitty compared to any normal language like C# or even Python. It is made by a game engine, used by thousands of people, instead of being made by gorillions of dollars poured into it by tech companies and used by millions of people. I'm just going to use good languages instead.
GDScript might be a bad general purpose language but it is a good language for Godot.
You say Python is a "normal" language for me while I love Python, modern Python has gotten way too complicated and clunky with lots of new features added. For me GDScript feels much closer to the original pythonic ideal. Plus it is much easier to learn for people that are not professional programmers.
Maybe you don't enjoy using GDScript and that is fine but saying it is a "objectively bad" language is really uncalled for. For many devs it is the right fit.
C# and GDScript are no different. They both have made design decisions for particular reasons.
You’re a skilled developer in real languages, so I’d encourage you to explore why other developers might prefer a DSL for their needs!