If you know c#, then .net6 released recently, which is a LTS release and has really cool features like hot reload, minimal API etc. It also has sufficient performance improvements as compared to its predecessors. As a language, personally I find C# to be much easier and better to use as compared to java/python, especially for web dev and C# 10 has some really good language improvements like record types etc. I have used it mostly in windows env, so, not sure about it's performance on Linux, but considering its cross platform, I'm guessing it would be good.
Honestly, I've yet to find a backend that is as productive and performant as C# + Entity Framework out of the box. I've tried a wide array of other products, but somehow for ease of use this really sticks out. Of course scalability maybe be in an issue in the long run with EF, but I don't know if simplest and scalability really go hand in hand.
