QGIS 3.16.3 uses Python 3.7.7 while I want it to use Python 3.9.1 already on my MacOS Big Sur

MacOS: Big Sur 11.1
QGIS: 3.16.3

KyngChaos said that QGIS 3.16 is using Python 3.9.X (strictly) and I installed this in my system, however the Python bundled with QGIS is 3.7.7. It is strange that the correct version is not bundled or supplied with QGIS itself.

I would like to know how I can change the Python from 3.7.7 to 3.9.1 in QGIS?