Few people will know Guido van Rossum. But if I tell you that thanks to him, computing is the way it is right now, it may surprise you, but that's how it is. He is the creator of the Python programming language. A universal and conservative language, since the evolutions throughout history have been few and have always been characterized by being compatible with the old versions. That is why perhaps Apple has already decided that it is time to eliminate this part in its orders and therefore not included in the macOS 12.3 Beta
Apple will no longer ship Python 2.7 with macOS 12.3. Based on the developer release notes for the next software update. This is a recurring theme for those who are users of this programming language. Python 2 has been unsupported since January 1, 2020 and no longer receives bug fixes, security patches, or other changes. So it is something that was seen coming, but it has already become official. That doesn't make it hurt less, for the record.
Apple says developers should use an alternative programming language instead, like Python 3. Now, it's worth noting that Python 3 doesn't come pre-installed on macOS either. Developers can run the /usr/bin/python3 stub via Terminal. However, users are required to install the Xcode development tools, which includes the third version of the open programming language.
These Xcode development tools do not come pre-installed on macOS. So that it will be necessary to install them separately to be able to work with them and be able to continue using Python. If you want to know a little more about Python and its relationship with macOS and the existing alternatives, it is worthwhile to etake a look at this documentation.