What chipset implements Bluetooth 5 on the 2019 Mac Pro

From Wikipedia “M.2 formerly known as the Next Generation Form Factor (NGFF), is a specification for internally mounted computer expansion.”

Apple does not offer M.2 slots, they created there own slot system used in the older MacBook Pro’s and iMac’s. In the new Mac Pro, iMac Pro and Mac Studio Apple went a step farther! These systems use a Raw Flash chip design removing the controller from the SSD board, all it has is a I/O buffer and ID chip. This then places the controller logic onto the main logic board interfacing across all of the Flash modules in a kind of RAID concept allowing much faster throughput!

The WiFI and Bluetooth services are not replaceable! But you might find a PCIe board which you could install. Then disabling the internal then using the boards services.

Now why do you think you need something newer than Bluetooth 5? Presently this is the newest standard. FYI - Mac Pro, iMac Pro and even the current Mac Studio offer Bluetooth 5 services.

Are you looking for WiFi 6 services? Only the Mac Studio offers WiFi 6

One of the problems we face is as the data rate increases the distance between gets shorter and/or narrow (focused) which is why some of 5G cellular connections are not very good!

If you need high throughput just use a wired connection! Ethernet is still over three times faster and can be more secure!