MB Pro with T2 chip has BlueTooth Stuttering problems

Whenever someone tells me they are having BT problems my first recommendation is that they unplug and turn off every peripheral device except for a keyboard and mouse. If you have a cordless phone or baby monitor near the computer all move or turn them off. If your BT problems disappear, one by one turn on and plug in the peripherals.

External hard drives and USB hubs & docks are often inadequately shielded and cables often have no shielding at all. If you determine that a specific peripheral device is the cause you may be able to simply move it to a new location or further away from the computer or mouse/keyboard. You may find that shielded USB cables are the answer.

BerkeleyScribe wrote:

After some reading online, I disabled auto date -time and time zone sync. That improved the problem, but it didn't completely solve the problem.

Bluetooth - Apple Support

Connect a Bluetooth device with your Mac - Apple Support

Using a Bluetooth mouse, keyboard, or trackpad with ... - Apple Support

Pair a third-party Bluetooth accessory with your ... - Apple Support

Resolve Wi-Fi and Bluetooth issues caused by ... - Apple Support

Apple USB-C Charge Cable Replacement Program - Apple Support

https://www.apple.com/support/usbc-chargecable/

see—Grant Bennet-Alder

https://discussions.apple.com/message/33794588#message33794588

USB C dongle kills wifi 

Why do I have difficulty with Wi-Fi or Bluetooth devices when USB 3 devices are attached to my computer?

Some USB 3 devices can generate radio frequency interference that can cause Wi-Fi and Bluetooth devices operating in the 2.4GHz band to have issues communicating with your computer. 

Here are some tips to avoid this issue:

If your USB device has a cable long enough that you can move the device, place it away from your Mac—and make sure not to place it behind your Mac, or near the hinge of its display. The antennas for Wi-Fi and Bluetooth are located there, and USB 3 devices placed there might interfere with your wireless connections.

If you're using adapters or dongles on a Mac computer with Thunderbolt 3 (USB-C) ports, plug them into the front port on the left side of your Mac, or into the ports on the right side (if your computer has them). These ports are the farthest away from the antennas, making interference less likely.

To avoid interference on the 2.4GHz band using Wi-Fi, try using the 5GHz band instead. You can change this on your wireless base station. Bluetooth always uses 2.4GHz, so this alternative isn't available for Bluetooth.

ref: Using USB devices with your Mac

https://support.apple.com/en-us/HT201163

anything using the same spectrum as BT could be the cause if the problem is interference. Location is part of the issue and if there’s something near the computer’s BT antenna causing interference that’s why the problem would affect it but not the iPad.