The group call feature was only included in the commercial edition you installed by accident. When you moved back to the Team Edition (9.x or 10.x), group calls were removed because they aren’t part of Team Edition.
To bring them back, you have two choices:
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Switch to the commercial edition with a license.
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Stay on Team Edition and integrate an external call tool like Jitsi or Zoom.
I recommend you decide whether group calls are essential so that you can proceed with the best option.