My company is about to start on a large API project. We have a large legacy WinForms app, and we need to move the data access for it behind an API so that we can build out a modern web app and modernize our supporting services. I'm doing some preliminary research on best practices and so on... questions in no particular order, also interested in any other input or suggestions people have.

• It seems like .NET Core is a given at this point, but how are its supporting libraries? Are there still any major pain points with EF Core?
• Handling authentication? I assume JWTs are probably the standard, is all the tooling for handling them built in, or any libraries I should be looking at?
• Libraries for helping with query params (search/sort/paging)? Would definitely prefer to avoid rolling our own if possible. I have some past experience with OData and wasn't a huge fan of it, hoping for something that's easier to use on the back end.
• General back end architecture? Have libraries like MediatR become more standard or do most people still lean towards a pretty traditional service layer and data access layer?
• Versioning? We'll have to deal with it eventually... anything we need to consider from the start?
• Documentation? I'm guessing Swagger is the standard, how is the tooling around it in .NET Core?