Are you sure that Xcode 12.1 is not supported by Apple? The latest version of Xcode is 12.3 which was released on 14-Dec-2020. Xcode 12.1 was released just two months earlier (on 20-Oct-2020). I can't find s statement from Apple about how long Xcode 12.1 will be supported, but I'd be very surprised (and disappointed) if Apple dropped support two months after releasing Xcode 12.1.
Incidentally, the Apple web page https://developer.apple.com/support/xcode/ seems to say that Xcode 12.1 can generate code targeted to macOS 10.9 (Mavericks) through 11.0 (Big Sur).
I don't think it is fair to try to blame this situation on Apple. The Intuit developers may want to take the easy way out and only use the very latest version of Xcode. However, the above referenced web page suggests that Xcode 12.3 can still support a deployment target of macOS 10.9 through 11.0.
Whether the decision was made by Intuit developers or Intuit management, it is a very unwise decision because it abandons many loyal customers.
