nostr:npub15hpepqae8vhx06xzkseynhy86lnmzttsnzasv9ahze4p7dlyyrms2skgyw crap, I only now realized that you can use Logic plugins in Final Cut! Just took a look at what's available and you could use the Noise gate, Denoiser or the Channel EQ (set it to a low pass filter).
https://support.apple.com/en-ca/guide/final-cut-pro-logic-effects/lgex9389203a/mac
https://support.apple.com/en-ca/guide/final-cut-pro-logic-effects/lgex92fd6e16/10.6.6/mac/12.6
https://support.apple.com/en-ca/guide/final-cut-pro-logic-effects/lgex931a105a/10.6.6/mac/12.6