homebrew - pyenv versions doesnt show anything after installing other version of python on mac big sur

Question

why it doesnt show my python version installations

% pyenv versions 
* system (set by /Users/axilaris/.pyenv/version)

I know I have Python 3.6 (that comes with Big Sur) and 3.8 and 3.9 (I have installed using Python .pkg installer - https://www.python.org/downloads/)

I have installed pyenv using

brew install pyenv

UPDATE (here are existing python I found existing in my mac):

% pwd
/Library/Frameworks/Python.framework/Versions
% ls -al
total 0
drwxrwxr-x   6 root  wheel  192 Jan 11 14:18 .
drwxr-xr-x   6 root  wheel  192 Jan 11 14:18 ..
drwxrwxr-x  10 root  admin  320 Nov  8  2017 3.6
drwxrwxr-x  10 root  admin  320 Jan  2 18:24 3.8
drwxrwxr-x  11 root  admin  352 Jan 11 14:18 3.9
lrwxr-xr-x   1 root  wheel    3 Jan 11 14:18 Current -> 3.9
% python -V  
Python 2.7.16
% python3 -V
Python 3.9.1


in another location

% ls -al
total 0
drwxr-xr-x   7 root  wheel  224 Jan  1  2020 .
drwxr-xr-x   5 root  wheel  160 Jan  1  2020 ..
lrwxr-xr-x   1 root  wheel    3 Jan  1  2020 2.3 -> 2.7
lrwxr-xr-x   1 root  wheel    3 Jan  1  2020 2.5 -> 2.7
lrwxr-xr-x   1 root  wheel    3 Jan  1  2020 2.6 -> 2.7
drwxr-xr-x  11 root  wheel  352 Jan  1  2020 2.7
lrwxr-xr-x   1 root  wheel    3 Jan  1  2020 Current -> 2.7
% pwd
/System/Library/Frameworks/Python.framework/Versions

Answer 1

pyenv versions only shows versions installed and managed by pyenv