And I believe Monogame is a little different, atleast.
Unity is different to Unreal Engine 4. A lot.
Yet many people make the transition one of both ways. Because, in the end, both are modern 3D engines that tackle similar problems in a similar way. If you understand how lightmapping works, you just need to know the quirks of the engine you use when it comes to lightmapping, and where the buttons are to build a lightmap.
Which in turn is easy to ask online, as it is a simple question: "where is the button to build a lightmap in UE4?"
As far as I heard XNA and Mono are much more similar. You might run into one or two differences that prove showstoppers in a tutorial. THEN you should come here and ask questions to be able to proceed in your chosen tutorial.
If you find a good XNA tutorial, just try it out, IF you want to go MonoGame. Chances are either there are no real differences, you will be able to figure out the few slight differences you find, or in case you find a bigger one, someone on a forum will be able to help you.
Don't complain about missing tutorials in this day and age. There are plenty online. They might not fit your problem exactly, or might be for a slightly different tool, engine or framework. But a lot of things transfer from engine to engine or framework to framework, because its a common principle or just solved the same way in both. And if you use common sense and some clever thinking, you can figure out a lot of the remaining things yourself.