KM717 USB universal receiver connection issue

I have been give a KM717 combo company lucky draw in 2020(made in 2019), in someday in 2023, the keyboard WK717 suddenly cannot connects to Universal Receiver, cannot be added to it. And #1 has been mixed with bluetooth. Now #1 and #2 are both Bluetooth to my laptop, #1 should be connected to my PC previously. 
https://www.dell.com/support/kbdoc/zh-cn/000128978/dell-wireless-keyboard-km717-km636-no-function-after-upgrade-dell-universal-receiver-firmware-updater-version-1-4-1-0-a00?lang=en 
this KB shows that maybe the universal receiver FW is the root cause. But this KB has been removed from Dell Support page. Calling Dell support personnel, just telling to reinstall BT firmware, I know that's nonsense, after reinstalling, no luck. Then she checks and says oh sir, your combo has been out of warrenty, cannot replace them per policy. And I tell them about the issue and show them the problem listed in community. But cannot get any useful feedback, just says it has not warrenty. Looks like it's a bug for KM717 and KM636. But the support guy just push back.
Anyone can help with this problem? Now, #1 and #2 are both for Bluetooth to laptop, cannot add the Keyboard using universal receiver panel (press any key and power one, no reaction). Try to use #3 and connecs it to my PC using BT, it shows Paired, but Not Connected. Also cannot use #3 on my PC. 

Dell support's feedback is very dispointed. 

Anybody has any ideas? Thanks in advance.