Popping speakers, FCA1616 USB-AUDIO-Interface

Setup: Asus TUF Z390-PLUS Gaming (WiFi) + Intel i5 9600K + RX580 (DP)

SW: macOS High Sierra 10.13.6 - SMBIOS: iMac 18,3

So I have a Behringer FCA1616 connected to my Hackintosh via USB. I recently created my custom SSDT for my USB ports which allowed me to reconnect the card via USB again as it, for whatever reason, provides me with much lower latency in both Ableton and Logic than the Firewire connection. However, previous to the creation of my custom SSDT, I was unable to use the USB connection due to a popping sound each time I initiated audio on my Hack (going from no sound to sound playing i.e starting a youtube video). This lead me to having to use the Firewire connection with a greater recording latency.

After creating my custom SSDT, I swapped back to the USB connection, all was well, almost zero latency, no popping, life was good - until yd, when the popping started happening again. All I was really doing was trying out the new (I say new, but it's really just new to me - a seasoned chrome user) Safari and out of nowhere, the issue appeared once again.

I installed a few app updates, namely the Safari 12.1.1, Pages 8.1, Evernote 7.11, Numbers 6.1 and also installed the uBlock origin extension for Safari but other than that - no changes were made to my system.

As this previously was only related to the USB-connection, I had deemed it a hardware issue and even been in contact with Behringer who suggested I send it away to Germany for evaluation under its warranty. After noticing it working again and that it now stoped working again, I did do some further research in to it and found that I was not alone in experiencing the issues I was, and finally got to this post at tonymacx86.

I tried out that solution and found that it only worked out for me personally when setting the sleep value to '0'. I then got no popping and only some static "crunching" every now and then. I was almost (although not) content, until I realised that this made the script run continuously, which in turn lead to a constant CPU load of around 10-12%. I then experimented with an array of values ranging from 0-20 which came out with various degrees of nasty popping and nothing that made the issue any better..

If I connect the card back via Firewire, I have no issues whatsoever, other than the obvious latency, which is also the whole reason I wanna keep it connected via USB.

I think that's everything - hope anyone has any ideas as to what to do next