Hi OrnaVH,
It looks like I was right, and the devices usually have a USB receiver that comes with them.
Because the receiver usually comes with a special fit at the factory, if you just buy a new receiver, it won't necessarily work with your ergonomic keyboard set.
If it's already broken, then I actually recommend you contact accessory support directly and check if you can get a new USB receiver from them.
I can direct you to parts support:
- Use your personal Microsoft account (not your organization account) to access the following links:
Contact - Microsoft Support
- Type ergonomic keyboard, press Enter, and click "Contact Support" at the bottom:

- Make a selection based on the screenshot below and click Confirm:

- You will see contact options for Chat support and Phone support, please contact them during business hours:

I wish you all the best.
As for Bluetooth laptops, let me kindly explain to you here that these are two different ways of connecting.
Connect your device directly to your laptop via Bluetooth, using your laptop's Bluetooth function, but your ergonomic keyboard can only recognize the signal from your USB receiver (or adapter), not directly from your laptop's Bluetooth signal.
Best Regards,
Mitchell | Microsoft Community Support Specialist