Switching to .Net - is it good idea?

Hi

I am thinking to switch from angular and golang to .Net

** What is the learning curve of .Net? Is it possible to switch without knowing anything except the basics of c#?

** I have to learn C#, ASP.Net, Blazor, and mssql

Is that right?

** Do i have to switch to windows from mac?

** For web app and web api, Can i use linux server for hosting?

** Is mssql free? And the .Net development free? Or should pay to microsoft for anything? Will this switch cost me anything?