To install a custom version of python, download and compile from here:
https://www.python.org/ftp/python/
MuEditor - requires python < 3.9 + install libsqlite3-dev before compiling
python3.8 -m venv mu-editor (create a virtual env in the mu-editor folder)
cd mu-edit/bin
source activate (activates in console the virtual env)
pip install mu-editor
To install python apps you use pip
Pip aplications: https://pypi.org/project/mu-editor/
Make shorutcuts for python apps while in virtual env
pip install shortcut
shortcut mu-editor