I was a counselor before I retired last year so I didn’t have a work environment like yours. However, I belonged to several organizations and groups helping people to use HAs. HAs are not effective for noisy or distances from speakers. I really love the ComPilot and FM Zoom-link as you have but do not have much luck in similarly described situations at a window that you have. I think that you should try a directional microphone and I think you will find something better than the Zoom-link in my opinion. I have tried a few and they don’t need to be expensive. You will, however, need to do your homework to find what will work for you. Looking beyond Phonak brand will yield good options for you.
Did you try Harris Communication? They can help but you should talk to a technician to explain your problems. Their website is www.harriscomm.com.
A couple of years ago I found a perfect item for $60. It was a BT reporter mic looks like a pen from Brookstones I found at an airport. Can’t find it online.
I better system than the Phonak lineup is a Pocket Talker with anFM transmitter and receiver coupled to a T-Coil neckloop.
See what Harris has to say then try something with the idea you can return it and try something else.