Hire a professional and don’t listen to these people. Your place most likely has metal studs and not wood. Do not use a full motion mount with drywall or into metal. Use a tilt or advanced tilt mount instead.
Yes, my drywall does have metal studs. What's the difference? Why can't you use a full motion mount with drywall and into metal? I don't get it.
I would need a full motion mount because my bed area (where I sit and watch the TV from) is not directly in front of the mounted TV. I need the TV to face sideways to the right.
Which is exactly why you use a cross member, between the (metal) studs. But, I'm out.
Good luck OP, with whatever you do.
Please continue helping.