I have the same Phonak HAs. And I have experienced all the issues you described connecting to my Mac computers and using Zoom. It seems like the HAs connect to various sources whenever they want and not what I want. I have even had them hijack my wife’s iPhone audio while she was talking even though they were never paired to her phone.
You have to remember that these HAs can only have two active connections at a time. So it is important to keep looking at the sound and BT status panels from the menu tab at the top of your screen. If you cannot get them to connect from those status panels, you should try to turn your HAs off and on, which puts them in BT connect mode. I have learned to turn them on/off quickly by pressing and holding the bottom of the rocker switch on the HAs. Alternatively, you can turn them off and on quickly by inserting and removing them from the charger.
At first, I had problems connecting with Zoom or GoToMeeting, but it seems to be working now.
I also have problems with sound quality on a phone call and even sometimes when I am just streaming some music from my phone (dropouts).
I have been frustrated with the BT on my P90Rs, but they work enough of the time to keep them. I think Paradise HAs are the only ones with a BT microphone, so I do not have to have the phone in hand to make a call. Other HAs apparently must use the phone microphone for phone calls. I understand the BT problems are common on most HAs. I wish there was an interface in the myphonak app that would allow control of BT connections.
I’m also looking forward to the next generation of BT 5.2 HAs that will eventually solve some of these issues.
Good Luck!