No, this is not true. macOS 10.15 included Python 2.7 as part of the OS, and it was removed in macOS 12.2 IIRC.

Python 3.9 is still included in Xcode and the Command Line Tools, but not the OS itself. It’s only for running scripts (and for supporting LLDB I think), applications cannot link against it like they could with the old OS-bundled 2.7.

Python 3.9 is getting conspicuously old though, I was a bit surprised Apple didn’t update it in Xcode 27.