Can 2 bluetooth keyboards be connected to IMac?

I have 2 wireless keyboards. The one connected to my iMac has some key problems. I can't get bluetooth to pair the other one which I have been using for Apple TV.

My bluetooth control panel doesn't look like the ones in Apple's instructions - there is no minus key to unpair the one I have been using on the iMac.

How can I swap keyboards from the Apple TV to the iMac?

Is there some reason 2 keyboards can't be connected to the iMac? I have a wireless numbers keypad and a swipe pad both connected and the work, as does my mouse.

TIA - Rick