2018 Outback stereo gone mad!

[James_AU]

So, maybe not "mad", however, it appears to have a hardware fault. It will work fine for awhile (5 mins, 2 hrs, ..) then it appears to have a ghost pressing buttons around the screen (typically top right area), which will throw the GPS navigation out the window, it will transfer calls back to the phone, then back to the car, then (you get the idea...). This will then make it impossible to do anything on the system, after a bit the car-ghost just holds it down and nothing will work (can't even press the soft buttons on the side for {home}, {map}, {phone}, etc... 

Since this car is now about 4 years old, I was thinking about just taking the Stereo out and replacing it with an aftermarket one (if possible..?).

I guess there are two questions here. 
1. Has anyone had this before? and is there a fix known? (I have just updated the software (with GREAT difficulty as the car-ghost was fighting me!))
2. Is replacing the Stereo system (just the screen/face part) an easy/affordable thing to do?

Any help/advice would be great! Thanks 🙃