The Razer Core X Chroma comes with a 0.5m Thunderbolt 3 cable. There is nothing wrong with the length, but the build quality of the cable is questionable.
I tested it with three MacBook Pros and all three experience frequent disconnections from the eGPU. It can be as frequent as once every 30 minutes. It is extremely irritating. Upon Googling, it seems to be a common problem.
I had enough of it and decided to buy the Apple Thunderbolt 3 (USB-C) Cable (0.8m) for S$59 or S$53.50 with Apple Corporate Employee Purchase Program (EPP).
After using it for a week, it works perfectly — no more disconnections.