The StudioLive 16.4.2 is only supported up to Mac OS X 10.14.6 (Mojave) with UC 1.7.6 available on the download page.
On Mac OS X 10.15.6 for StudioLive 1642, 2442 and FireStudio series interfaces, Installing FireWire Drivers in the UC 3.x installers will allow the audio I/O (FireStudio) device driver to appear in your DAW like Studio One, however Universal Control / SL will not work, therefore these configurations are not supported past Mac OS X 10.14.6.
The reason the device driver appears as it's the same driver that's used for the Ai Series mixers and StudioLive 1602-1394) which use UC Surface for control.