Based on our research, this function is not available now in Teams. There is no way to know who lowered the hand of another participant in Microsoft Teams. If you're a presenter or organizer of the meeting, you can lower everyone's hand at once.
Meanwhile, to get this feature more quickly, we recommend you give the feedback in Teams UserVoice. Many features of our current products are designed and upgraded based on customers’ feedback. With requirements like this increase, the problem may well be released in the future. Thanks for your understanding and support.
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