I would start with ASP.NET Core in Action (let me know if you'd like 40% off, I have a coupon code). The entire book is operating system agnostic. Sure, there are parts which go into Visual Studio specific things, but the majority of it is OS agnostic (the first chapter is along the lines of "if you are running Ubuntu...; whereas if you are running MacOS").
It's a little self-promotiony, but all of my articles on .NET Core where written using a combination of MacOS and Ubuntu 16.04/18.04 and VS Code.
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