Yes im sure becouse when i conect keyboard on windows 10 i have dual boot i ON BT in windows and add new keyboard + parring and windows give me only short number to write on keyboard and when i write example 56789023 and enter keyboard is instant connected. In linux i cant have that message then i connect BT adapter on USB and i paring using "Janky Bluetooth" and also work.
dmesg | grep -iA2 blue I use that comend and nothing happend any error message in terminal or grep info...
Is no problem coz keyboard work anyway and usb BT also i can use, but i wont try connect keyboard same as in windows without BT dongle. 
That coz keyboard dont have any but work with phone Mac, android, windows 10, but not suport linux, Then i try that dongle and work also... But is any way to paring this like in others OS? without use BT dongle...

This is my PC Specs meybe that help. I must check Motherboard BT module egsist or not. But if not then how windows 10 see keyboard? 
My motherboard spec info:
https://pl.msi.com/Motherboard/B450-GAM ... cification