Connect to Logitech K780 keyboard via Bluetooth

I'm using Linux Mint 22 Wilma, kernel 6.8.0-44-generic. My bluetooth adapter is a Qualcomm Atheros AR3011. It's a little old but it seems to work with most things. I want to pair with a K780 keyboard. The keyboard pairs fine with my Android phone, and my phone pairs fine with my computer, but the computer doesn't see the keyboard. I tried going into Code:bluetoothctl. The phone appears when I issue a Code:devices command but the keyboard does not. I got the MAC address for the keyboard and tried connecting to it directly via a Code:connect command but it says "Device not available."

I'm prepared to hear that I need a new adapter (this is a Low Energy device, maybe that matters?) but I could just be overlooking something done, I would appreciate any suggestions people may have.