Should I learn ASP.NET?

Hello Everyone,

Less than a year ago I graduated from college with a degree in CS. I have been working for a small company, but there isn't much upward growth potential in the company. As well, I have been jumping around from project to project using Angular, python, sql, asp.net, ... Although I enjoy getting exposed to every aspect of programming, I have realized that I enjoy backend development the most.

My question is should I learn ASP.NET? I will probably be at this company for another year, but I would like to expand my knowledge of backend development, so I can get a job in this position. So...

Is .NET the best backend framework to use?
Is .NET being overtaken by something else?
I want to work in a large company (whether it is financial, tech, or some other field). Is there and industry standard for large corporations?

Any advice helps thanks!