Desktop Hub not recognising 2nd external monitor (it is mirroring not extending)

Hi MattBlackFedora,

Thank you for using Apple Support Communities.

When you have a chance review these articles to see if it helps:

Use one or more external displays with your Mac - Apple Support

"If your Mac doesn’t detect a connected display

1. On your Mac, choose Apple menu  > System Preferences, then click Displays .
2. Click the Detect Displays button. (You may need to press the Option key to see the Detect Displays button.)

You can also try putting your Mac to sleep and then waking it."

If your external display isn't detected or appears blurry when connected to your Mac - Apple Support

You can also see if the same thing occurs with safe mode and a test user account:

Set up users, guests, and groups on Mac - Apple Support

How to use safe mode on your Mac - Apple Support

These steps can help narrow down the issue.

Given that you had no issues with the older hub, and none of the steps above helped, you may need to contact the manufacturer for further help with this. They can be reached here: bon.elk - Contact Us

Take care.

The Mac does not support TWO displays on a single cable unless the first device is a genuine ThunderBolt device on a genuine ThunderBolt cable. USB-C will NOT suffice.

You new dock is a USB-C dock. That is not good enough to run two displays.