Hi mate
There is a challenge with virtual serial ports on Mac. There are couple SW pieces on web, which pretend to do VSPE-like functionality in MacOS, but all buggy as hell. Some of created virtual ports not even recognised by SDC (not SDC fault).
Couple ways to override the problem (as g0cgl mentioned, you have to create serial emulation on Mac first):
1. You may try to buy HW serial emulator based on USB/PL2303. It means waste of one USB port on you Mac. And there is no guarantee it will work without heavy dancing around.
2. You may plug Arduino/ESP32 into Mac's USB and use emulation of RS232 on Mac (there are heaps of examples how to do that in Arduino code, but it assumes you are OK to code yourself, at least the Arduino board). Again, it means waste of one USB port on you Mac (unless you find what else this Arduino can do for you except of just serial emulation). At least Arduino based port is recognised by SDC.
Further option may be really heavy for you current setup: move away from serial-based Xlog application and start looking towards TCI. (I guess that is what we all going to be doing in next few years anyway).
TBH, when I was solving the serial emulation issue on my Mac few years ago - I just decided to write my own log for Mac