Dear Ryno,
Thanks for reporting the issue here, we appreciate your effort and time to share the experience and I'm very sorry that you can’t access your Macro-enabled files, which has caused inconveniences to your daily work!
As mentioned in this article Macros from the internet are blocked by default in Office - Deploy Office | Microsoft Docs
To help improve security in Office, we’re changing the default behavior of Office applications to block macros in files from the internet. With this change, when users open a file that came from the internet, such as an email attachment, and that file contains macros, the following message will be displayed:

If you right click the Excel file and go to Properties> in General tab, can you find a check box for Unblock? If yes, select the checkbox and then check if you can run macro in the file.
If you cannot find the Unlock checkbox, could you share with us the version and channel of your Excel application?
Thank you for your understanding and time.
Sincerely,
Edwine | Microsoft Community Moderator