My new appletv remote does not work how check whether appletv or remote is at fault?

Did you get a replacement remote?

What is your model Apple TV? Identify your Apple TV model - Apple Support

What is your (new) model remote? Identify your Apple TV remote - Apple Support

Older models Apple TV (3rd generation or earlier) cannot use the Siri Remote. Instead they will need the remote of their own era. Currently not for sale anymore through Apple, but other resellers may still have a few.

The Siri Remote requires Apple TV (4th generation or later). The Siri Remote (1st generation) is compatible with versions system software tvOS 9 or later. The Siri Remote (2nd generation) requires tvOS 14.5 or later. The Siri Remote (3rd generation) requires tvOS 15.4 or later.

Replacement remotes will need to be paired or linked. That is described in this support document: If your Siri Remote or Apple TV Remote isn't working - Apple Support

Apple TV has no id

Identify your Apple TV model - Apple Support. If the images and descriptions in the support document alone don’t give a definitive clue, then the device should also have an A-number on the bottom, and in the Settings﹥General﹥About﹥ menu (A1218, A1378, A1427, A1469, A1625, A1842, A2169, A2737, A2843).

control had no id

Identify your Apple TV remote - Apple Support. If the images and descriptions in the support document alone do not give a definitive clue, then the remotes should also have an A-number on the backside (A1156, A1294, A1513, A1962, A2540, A…).

seems to me that jt is easier to use the Apple tv app on my Sony smart tv?

It is not the same. Apple TV app vs. Apple TV box - Apple Community. Whether the differences are compelling (enough) for you, that is a choice that only you can make.