You need a
cross-compilation toolchain with a dozen of packages added to
build Python.
Another annoying thing is that you would also need a bunch of other packages to make Python useful (pip, wheel, venv...)
Probably the simplest way to get Python is to use a
full Linux in chroot environment, that already has Python. It works well for running scripts, but will be less integrated (e.g. no Python-based KUAL extensions...)