Pyenv allows the usage of several python interpreters on the system:
C:\Users\Mindaugas\Desktop\deletethis>python -V Python 3.7.4 C:\Users\Mindaugas\Desktop\deletethis> cd ..\deletethisalso C:\Users\Mindaugas\Desktop\deletethisalso python -V Python 3.9.6
Note, that if you see the system-wide python interpreter version and other versions are not turning on when using pyenv check whether the systems python interpreter is in the global system path or local user path (on windows). Remove the entry if that it the case and you should be able to switch with pyenv.