Successive audio crackling in fairlight

When I click "arm recording" in fairlight (after patching the audio input to "Audio 1-L" and "Audio 1-R"), I immediately hear my own voice with a repetitive clicking/buzzing noise.

Here's an example of it:

Edit:

Seems this guy had a similar issue:
viewtopic.php?f=21&t=85467

but the solution he posted is not working for me.

I have this on the Windows and Mac M1 version; recording from an AT2020 into a Focusrite the audio is just garbage - though I think in my test I forgot to tweak a setting. It's perfect in Reaper though so I'm at a loss as to why it's just a mess 'normally'.