I want the notetaker to leave a meeting I'm currently in:

Remove the notetaker using the live notetaker control feature found in the top left corner of Jump:

Clicking this red button will remove the notetaker from the call, which is particularly useful if you aren't the host.

Clicking the gray pause button will pause the notetaker's ability to record the meeting but will not remove it from the meeting.

I want to prevent the notetaker from attending an upcoming video call:
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Toggle off the notetaker in the "Upcoming" meetings tab:

I want to prevent the notetaker from attending all my video calls:

Go to User settings > Preferences > Calendars > Toggle off "Automatically add notetaker to upcoming meetings"