Recording your Zoom video and audio calls on your Mac is a piece of cake with Screenflick.
By default, Zoom's audio will be recorded by Screenflick, but if you've changed the Zoom audio output device (for example, to your headphones) you'll need to change that setting again. Inside Zoom's settings, if you simply select the "Same as System" value for the "Speaker" setting in "Audio" preferences, you should be good to go. To change which device you hear Zoom calls on, select the device in System Preferences → Sound → Output before starting the recording, or change it in the Screenflick global menu.
In System Preferences → Sound → Output, select your headphones so the other chat participants' voices don't get picked up by your microphone.
In Zoom → Preferences → Audio, you should prefer to select "Same as System" for the "Speaker" setting. If you do that, you should always be able to hear and record Zoom with no problem.
An alternative choice is to select "Screenflick Loopback" directly instead of Same as System. Note that after changing this setting, you will not hear any audio coming from Zoom UNTIL you start a recording in Screenflick. After you start the recording, you will hear everything just fine.
Most users will also find that simply selecting "Same as System" instead of Screenflick Loopback will work properly, and requires no changing of the settings when recording, but selecting Screenflick Loopback is the surefire way to know it will be recorded.
Lastly, Inside Screenflick, select your microphone device and turn on Record System Audio as well.
After you start the recording you will hear everything as you expect, and you can even check in Screenflick's global menu in the right side of menubar and see the audio level indicator changing as you and others chat in Zoom, to know that audio is being recorded.