Call Control and Call Companion

Given the glaring absence of call control for Zoom Appliances, I've been experimenting with a Yealink SipT31G.  Whilst both of the above functions do what they say on the tin, there doesn't seem to be any way to have both enabled at the same time.  If i have call control enabled, I can click dial from my Zoom client, just the way I did with Skype for Business.  If I then start a meeting (with call control still enabled), the line key assigned for Zoom meetings stays green.  However, if I disable call control, then start a meeting, the assigned line key turns red and I can use it to join the audio portion of the meeting from the phone.

Am I missing something?  Functionality wise, it seems that we have gone backward from where we were.  None of these were an issue with Skype!  Frustration levels are high at the moment - we're trying to provide a seamless experience for our users, but it just seems as though the 'unified' element is missing.  It's all very disparate.  We are primarily a thin client site, so there is no desktop audio.  We currently have old USB phones plugged in to get around this.