.NET core is open source and has worked on windows, mac os, and linux for a while now. I started working on a front end for a C# .net core project recently which is being developed at a primarily Windows shop and I got it running on Ubuntu in 15 minutes. I would have died before picking a Microsoft stack for a project 5 years ago, but the back end for my next project will be .net core. The developer experience and tooling are second to none these days. You really should give it another look.