In current state, Debian does not contain a /usr/bin/python file, and since 2.7 is eliminated from system relatively long time ago, everything is python3.
If you really in dire need, you can install "python-is-python3", which just symlinks /usr/bin/python to /usr/bin/python3. However, no package can depend on it in Debian. It's strictly verboten.
If you really in dire need, you can install "python-is-python3", which just symlinks /usr/bin/python to /usr/bin/python3. However, no package can depend on it in Debian. It's strictly verboten.