No one has named Haxe / OpenFL. The step is much closer to the Flash ecosystem than any other solution. Maybe the problem you have with the ANEs or extensions necessary for Android and iOS development (you should ask in the OpenFL forums). With OpenFL you do not need Starling. It's like Flash / as3, gpu mode.
If you focus only on games there are other alternatives. C++ I see it too far for your type of knowledge. I think Unity working with c# will be closer to as3.
What I would do is dedicate myself to do some "simple" projects in AIR to start. In two years I do not think it will go anywhere (there will continue to be support for the latest updates on Android and iOS, except catastrophe)
I would look at OpenFL at some point. Maybe it is what you are looking for and it is much closer to your knowledge.
And if nothing convinces you, go to Unity directly. There is a lot of online support and a huge community (and a long-term assured future).