• https://realpython.com/intro-to-pyenv/
• https://askubuntu.com/questions/682869/how-do-i-install-a-different-python-version-using-apt-get

For fully automated installation:

curl https://pyenv.run | bash

Manual installation steps:

git clone https://github.com/pyenv/pyenv.git ~/.pyenv
 
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'command -v pyenv >/dev/null || export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
 
# Restart shell to apply new PATH variable
exec "$SHELL"

git clone https://github.com/pyenv/pyenv-update.git $(pyenv root)/plugins/pyenv-update
git clone https://github.com/pyenv/pyenv-virtualenv.git $(pyenv root)/plugins/pyenv-virtualenv

sudo apt update; sudo apt install build-essential libssl-dev zlib1g-dev \
libbz2-dev libreadline-dev libsqlite3-dev curl \
libncursesw5-dev xz-utils tk-dev libxml2-dev libxmlsec1-dev libffi-dev liblzma-dev

# list of all available versions
pyenv install -l
 
pyenv install 3.11

$ python3 --version
Python 3.9.2
 
$ pyenv global 3.11
 
$ python3 --version
Python 3.11.4
 
$ pyenv global system
 
$ python3 --version
Python 3.9.2