You may be able to eliminate the noise by changing your grounding scheme. Ground the USB hub by powering it. Plug its power into a power strip. Plug the MODX into the same power strip and plug everything else into that same power strip.

Also, there are different approaches to shielding and termination. To tie the shield to digital ground - or just chassis ground. Both sides vs. one side. Etc. Some of these decisions are made at the device itself (MODX, USB hub, laptop, etc). But the cable itself has some chance also to possibly "override" a decision by the way the cable is constructed. Different USB cable part numbers from the same manufacturer (or different ones from different manufacturers) may have different properties and yield better/worse results. This is taking out of consideration filtering such as use of beads which also can have some impact. Although you should be able to "get there" with a "proper" grounding scheme outside of employing beads.

If noise is "fixed" by NOT changing the USB and device grounding - and you can keep this the same and apply some form of filter ONLY to the MODX audio outputs to fix the problem - then the issue may not necessarily be ground loop related. It may still be - but the problem may also be injection of noise your audio cables through a more direct path of crosstalk between the USB cable and audio cables. Which using a transformer to convert MODX's unbalanced outputs to balanced outputs can help here because balanced cables are not as susceptible to this form of noise injection. Quickly converting to balanced straight out of MODX may help you (shortest, most direct run as unbalanced before conversion). Some conversion can be done with something that looks like a 1/4" plug (TS) on one side and XLR on the other side with no cable between.

I would first try to investigate how all devices are powered. How they share a common power strip - or are going to different power sources through different paths. And try to reign that in first. Because the solution is, generally, fairly low-cost and simplified vs. trying to add isolation/impedance conversion on your audio path.

This helped.

The problem is that both the Mac and the Modx are not grounded. The Mac uses a two pin power connector and the Modx uses a power adapter.
It's the cheap version of the Montage for a reason and ground hum problems is one of the possible results of that.

Disconnecting the usb-ground between the mac and the modx did the trick (see picture attached)

PS. This is not my picture so kudos to the person who made it. The original picture had the tape on the right hand side but that did not work for me. This did. Either way it separates the usb power between the mac and modx.