It's easy to underestimate the risk when installing wiring.

Gain an understanding of the regulations and real-life applications.

#1 Do not violate the 2020 NEC code compliance.

The 2020 NEC Code Compliance states that flexible power cords hidden behind a wall are a violation of the National Electric Code and could void your home or business insurance coverage.

#2 Follow 2020 NEC code compliance

The following is an excerpt from (NEC) – NFPA 70

400.8 Uses Not Permitted. 

Unless expressly permitted in 400.7, flexible cords and cables shall not be used for the following:

As a substitute for the fixed wiring of a structure.
Where run through holes in walls, structural ceilings, suspended ceilings, dropped ceilings, or floors.
( Where run through doorways, windows, or similar openings.
(4) Where attached to building surfaces. The exception to (4): Flexible cord and cable shall be permitted to be connected to building surfaces under the provisions of 368.56(B)
Where concealed by walls, floors, or ceilings or located above suspended or dropped ceilings
Where installed in raceways, except as otherwise permitted in this Code.
Where subject to physical damage
No Power Cords Inside The Wall

In plain and simple to understand words, it explains how running power cords through the walls is not a substitute or suitable instead permanent wiring.

A new electric outlet installed directly behind the TV is what is required.

#3 Power cables are not rated for in-wall use

Additionally, your home or business insurance company will be happy to void coverage should a fire result.

#4 Safety surpasses monetary gain.

If any professional installation company advises it is fine to run power cords inside the wall, then those inexperienced professionals may not be aware of the (NEC) National Electric Code requirements or are more concerned about shortcuts than the personal safety of those who they call clients.