Noob. Buying a new machine solely for Linux. What should I look at for?

It will be used for steam link gaming as well as heavy programming (c++, c#, JavaScript, unity). I am a Linux noob but want to make the jump from Windows for many reasons (only 2 pieces of software I will find it difficult to live without). This pc will cost me a fair bit of money and I want to make sure it will support a Linux OS well (distro undecided right now). I am thinking of using a site like pcspecialist where you select components from a list and they build it and ship it. What's the best way for me to tell that a Linux distro will run on it?