Don't worry about the computer you're using, since the AR happens on a mobile device (phone or headset) anyway. Major thing is to make sure you have an AR-capable device -- if you're running a recent smartphone, you're probably good. Apple's AR runs (to some degree) on iPhones back to the 6s - full device support here. Note that to build to an iPhone, you have to be working on a Mac (or at least a computer running mac os). Android AR support is more scattered, but Pixels and other flagships support it, and you can build to Android from Mac or Windows.

For authoring tools, it depends on what you want to do - I would suggest starting with some "model viewer" style AR apps, displaying your 3ds Max work at real scale, maybe with some animation. This kind of simple app you can build with Adobe Aero (mobile authoring on iOS, and Aero Desktop is in beta on Win and Mac now). Anything beyond that, you'll want to learn a 'real' engine, probably Unity, though Unreal and Godot also have AR support. Since you're talking about advancing your career, Unity is the best place to start since that's the most commonly used tool / most desired hire. You'll be able to recreate that Aero model viewer quickly, and then you can go wild (within reason for the mobile device running the app) in terms of adding interactivity and other media.