Is this possible to do if macOS itself has the driver implemented as a DEXT?
If your hardware communicates entirely using standards-based protocols, you can ship a driver that matches your hardware to one of the built-in system drivers.
Particularly, I'm interested in providing support for an FTDI device with a custom product ID in my application. I've understood that macOS implements the FTDI driver as a DEXT (/System/Library/DriverExtensions/com.apple.DriverKit-AppleUSBFTDI.dext).
In Catalina, it's possible to work around this problem by instructing the users to install FTDI's custom KEXT driver, but that doesn't work anymore in Big Sur because the KEXT is blocked there.