If you find that your TECKNET Bluetooth Mouse keeps on disconnecting from your Windows 11 PC, there may be a simple fix. I had a problem where after roughly 4-5 minutes after the PC started, the mouse would disconnect, and then only reconnect if I held the Bluetooth button down and went through the setup process again.
I fixed this problem by going into "Services" and "Bluetooth Support Service".
Make sure that Bluetooth Support Service start-up type is set to automatic. You may need to restart your computer, and reconnect your Bluetooth mouse.