By connecting up to my MAC via USB C, I was able to restore the Apple TV to tvOS18.5.
Then your unit is an Apple TV HD (4th generation), model A1625. Earlier models wouldn’t be able to run tvOS 18.5, and later models wouldn’t have a USB port to connect to a computer.
When I plug it in and connect up HDMI, I get the Hello message in all the languages and cannot get past that.
It is waiting for user input from a connected Apple Remote (or connected bluetooth keyboard).
I tried pairing an Apple bluetooth keyboard, that did not work
It is possible, but would need to be done at startup, before the Hello message with the language choice comes on. I haven’t done it, but it is supported, when doing the procedure just right. I think a compatible keyboard must already be in pairing mode, as the Apple TV box starts up.
I tried plugging in a USB keyboard, again no joy.
The USB port on the Apple TV box is only for restoring the system software; only for connecting to a computer.
I have the Apple Remote app on an iPad but it will not recognise the Apple TV.
That could only work after you have set up the network settings on the Apple TV box. The communication between the iPad and the Apple TV box goes over the home network.
You are advised to buy a replacement remote. You can buy a historical black Siri Remote (1st generation) if you can find it, or the newer (better) brushed metal Siri Remote (2nd or 3rd generation). You can buy at trade platforms like eBay or Amazon, or buy the latest model remote directly from Apple.
List of various models Apple TV remote and their compatibility - Apple Support
Buy Siri Remote (3rd generation) - Apple TV Accessories - Apple Store online (US)
Normally, replacement remotes need pairing again, but perhaps that step can be skipped for units that haven’t been set up yet (just like new units do the pairing automatically).
