Tom at Villages AV has probably installed over a thousand flat TV's. Go to the search at the top of the page and type in "villages av", you'll find dozens of reviews, all good. I think he charges about $250, that includes everything parts and labor, all wires will be hidden and the TV will be mounted. He's a villager, lives in St. James, I had him help with my attic antenna. You can reach him at Phone: (352) 388-1677.
What I did for a wall mounted TV in a BR was I had a cable outlet and electrical outlet on a wall hidden by a dresser. I picked up this kit at Home Depot for about $40 and hide the power and cable wires behind the drywall. I bought the TV wall mount from Amazon for $30, it wasn't as hard as you would expect. When you look at the link, it appears the wires are visible, but they aren't, they are behind the drywall inside the tubing. You'll just run coax up the tube but you'll have an electrical plug at the top and bottom.
https://www.homedepot.com/p/Commerci...2-KW/204412643
They show 6 in stock at Lady Lake Home Depot. You'll need an electric drill, they provide the round drill bit that will make a hole at the top and bottom. Then you run tubing from hole to hole, and then mount with a box at the top and bottom. The only problem was a cross stud blocked my original path, so I had to start the bottom a little higher than I anticipated.