Most wall TV brackets are wide enough to span 16" studs with at least half offset to one side or another, and they have holes spaced about every 1", so you shouldn't need blocking for that.
What I did was to put an electrical outlet up behind the TV as well as an empty hole with a pull string that could later be used to fish cables to the TV. You can get AV trim plates with brushes or covers that let wires/cables come out neatly:
https://www.lowes.com/search?searchTerm=av+trim+plate
These can be mounted directly to drywall using an "old work" box plate:
https://www.lowes.com/pd/CARLON-1-G...dard-Rectangular-Wall-Electrical-Box/50385688
Then you just run the wires/cables inside the wall cavity. As long as they are low voltage (or data/RF) it's allowed. It's just the electrical that needs a proper outlet and box.
The other thing I did, that I thought was clever, was to designate a first floor closet as my "AV hub" and have all ethernet, phone, and cable TV wiring run to that closet (with some spares and pull strings to the attic and crawl). That's where I have all our internet gear, phone hub, and TV antenna distribution setup. The raw wiring comes through the wall using one of the AV plates above, and then I ran it to the various pieces of equipment that sit on a shelf or are mounted to the wall.
I had a structured wiring guy give me a quote and he wanted about $500 for a special metal AV cabinet for the same purpose, and I kept trying to tell him "no, the whole closet is my cabinet". Why the heck would I spend big bucks on a cabinet that is hard to work in when I have this 4' x 5' closet I can actually stand in, it has a full size door for entry/exit, and I have power outlets there, a light, and shelving. He finally caught on. Of course he got the neighbors to pay the $500 for the dinky AV cabinet in their house, so I figure it must be a pretty easy money grab....