Thanks for the reply, Erel , but the app that I linked to in my OP does pair with my laptop and works without any additional app on the laptop.
'Bluetooth Keyboard & Mouse' app available in Play Store: https://play.google.com/store/apps/details?id=io.appground.blek&hl=en&gl=US
If you have time, please do check it out and perhaps suggest how they are able to do it ?
Thanks
Like @GoodGuyOnWeb i have tried the "Bluetooth keyboard and mouse" App. It works like a charm on a Samsung A23 / Android 13 and connect the phone on Win10 as HID (If you have a previous non HID connexion from the device to your PC, forget first this pairing). Maybe is an enlightenment in the link below. If i'have got some time, i will explore it. https://github.com/kshoji/BLE-HID-Peripheral-for-Android
Interesting. Does this app work with BLE or classic Bluetooth?
I wasn't familiar with the BLE HID protocol. This will require implementing the specific protocol. You will need to modify BLE2Peripheral library for this. Not simple.