Open the meeting, tap ⋯ and then Save audio. The recording is saved to your phone's Downloads (or shared to the app you pick).
Open the meeting.
Tap ⋯, then Save audio.
The recording is saved. On Android it goes to Downloads, and you can tap to open the folder.
Good to know
Save audio only shows while the meeting still has its recording. If you deleted the recording or use auto-delete, the notes stay but the audio is gone.