I've been using MonoGame for the past year for cross-platform, and it does rock! You can now also use it in .NetStandard which you could not a year ago. It is actively being improved and there is a great community that can help. Also, there are lots of examples out there to help get you started.

Haha, sadly I understand the situation all too well. Having to scan means uncovering the all-in-one so that I can open it, then unplug all the cords from my laptop (which is difficult to replug back in because the power cord has to be positioned just right so that it charges), move it across the room and plug it in, wait for it to scan, reposition it if the page didn't scan correctly or moved. It's a 10 minute ordeal when I can get just as clear and well positioned document with my camera in half a minute.

Very true, but I have seen worse from home scanners

Frankly, I see the all-in-one printer going to the wayside. Unless I have to scan 10 documents together as a group (which is rare), I just snap a photo of the document with my phone and send it email.