Touchpad of the Apple TV remote

what is the button compination to restart the remote ?

Screenshot from the link provided by @urquhart:

Please try the procedures as described in: If your Siri Remote or Apple TV Remote isn't working - Apple Support

• Charge the remote if needed,
• Restart the Apple TV box (disconnect from power for a minute or so),
• Restart just the remote, using the button combination,
• Pair the remote again, using the other button combination.
• If you still need help after that, then contact Apple Support.

Or do yourself a favour and get a Function 101 remote instead. I just got one and what a difference it makes! The Siri remote, while lovely to look at, is awkward to hold and has limited controls. The Function 101 remote, on the other hand, gets rid of the trackpad altogether, replacing it with arrow keys that are far more accurate than that mushy trackpad! It also can turn your TV and soundbar on. Mine did it right out of the box, but you can also have it learn the correct codes for your setup. (I do not work for the company that makes Function 101, I just love it!)