bluetooth mouse and keyboard starting to slow

Please restart the computer in Safe Mode per the directions in the  How to use safe mode on your Mac - Apple Support link. 

Note: If you are using a wireless keyboard please either plug it in using the supplied Lightning cable that shipped with it. If you are using a legacy keyboard or a third-party keyboard that does not have re-charging abilities, please use any USB keyboard. Also note that a Safe Mode restart may require you to hold down the shift key for up to 5 minutes before the computer starts in Safe Mode. You will know it is in Safe Mode when you see “Safe Mode” in the upper right of the display.

After restarting in Safe Mode, then restart normally and test.

If for some reason a Safe Mode restart does not work, please do the following:

The following will require any USB keyboard and mouse. If you don’t have them, borrow or buy them, they are inexpensive!

1.     Connect the USB keyboard and mouse to the computer.

2.     Open System Preferences – Bluetooth

3.     Un-pair the wireless keyboard and mouse.

4.     Turn off Bluetooth

5.     Restart the computer in Safe Mode per the directions in How to use safe mode on your Mac - Apple Support

6.     Restart the computer normally.

7.     Open System Preferences – Bluetooth

8.     Turn on Bluetooth

9.     Re-Pair the wireless keyboard and mouse.

10.  Unplug the USB keyboard and mouse and begin testing the wireless devices again. 

Hey, how's it going?

You can try the following to resolve this issue:

• Change mouse and keyboard batteries. if it is rechargeable the battery may not be charging
• Try using a different USB port
• Go to the manufacturer's website and check for driver updates for your device
• Realize if the slowness is just on the device or the operating system as a whole. Often it can be another problem that is causing it

I hope you can solve this problem. Hope this helps

A hug, Descomplicando

You're welcome, please marked the thread as solved, this may help another user with a similar problem.