Clearing codes may very well eliminate your issue. You may need to clear codes, disconnect/reconnect 12V battery, clear codes, and repeat the sequence 2 or 3 times to get all errors cleared. If the issue comes back right away, then the intelligent brake controller is probably failing. I had that issue on my 2015 and just cleared the codes whenever it happened. The failures eventually became more frequent so I finally had the brake controller replaced under the extended warranty that I purchased when I bought the car. I would have just continued to clear the codes if I had not been able to have the controller replaced under warranty. Make sure your 12V battery is not getting weak since a weak battery can cause communication errors on the CAN Bus (which can then cause the ABS error codes and malfunctions). Due to CAN Bus communication issues, it may take several attempts to get all of the error codes cleared.
Incidentally, the $4,500 estimate seems high and there is not much risk of the wiring harness being bad. The cost of the intelligent brake controller should be closer to $3,000.