Dear Helen,
Hope this finds you well.
Based on your description, looks like you need to limit access to a transcript after a meeting.
Did further tests and consults on my end as well and I'm afraid I couldn't find a way to achieve this. Currently, there is no built-in feature in Microsoft Teams to limit access to a meeting transcript after the meeting has ended. However, as a workaround, the meeting organizer can download the transcript, delete it from the meeting chat, and then share the transcript with selected individuals after summarizing it.
I do understand your need for this, and we will surely raise your concerns with our product team and hopefully this can be included in future updates.
In the meantime, I do think that this would be a great addition to the teams meeting experience. If you don't mind, please provide feedback on this feature request by creating a new post in the Feedback Portal in Microsoft Teams · Community. Microsoft is committed to improving the customer experience by continually reviewing suggestions to include in the design and development of future product updates based on your suggestions.
Your kind understanding is greatly appreciated.
Thank you for your precious time and have a great day.
Best regards,
Ashraf.