v5.8.1 build only finds /usr system python3

I am building a CANONICAL edition of v5.8.1 with python support, however I am struggling to set the python3 library, executable, include dir, etc. away from the system python3. As a result, all my downstream scripts fail bc there is no numpy, etc found. I am on ubuntu 20.04 so it finds

Python3_LIBRARY_RELEASE:FILEPATH=/usr/lib/x86_64-linux-gnu/libpython3.8.so

Manually changing the python3 CMake variables gets over written with each configuration.

Setting any and all hints from FindPython{3}.cmake does not work either.

How can I point CMake to my own install of python with all the module I need?

Thanks!

As mentioned in the FindPython3 docs, setting Python3_FIND_STRATEGY to LOCATION will make it prefer finding a Python in a given location. Otherwise the behavior is to find the newest Python and then use that for everything.