Hope this helps someone.
I had the exact same issue. I had the ProApps bundle but my macOS version (monterrey) couldn't download them.
I didn't know anyone with a mac laptop I could use, so I just used my iPhone app store to enter the codes and it worked!!
As long as you have an iPhone 6s or higher updated PAST iOS 13, you should be able to input the codes in the appstore on your phone.
- Open the Apple appstore on your phone
- Click your profile in the top right
- Select, "Redeem Gift Card or Code"
- Select, "Enter code Manually"
- Enter in the code (it does all CAPS for you automatically)
- Hit Redeem
- Success! Go to your account on the appstore on your Mac, to verify the app is on your account.
When I hit the download button on FCP, it asked me "Download an older version of Final Cut Pro? The current version requires macOS 13.5 or later, but you can download the last compatible version."
So you will still be able to use these apps on your older Mac!
I hope this helps! Thanks so much for this thread!