Here's what I do:
brew upgrade --quiet pyenv
OLD_VERSION=$(cat ~/.pyenv/version)
NEW_VERSION=$(pyenv install -l | awk '/^[[:space:]]+[0-9]/ { sub(/^[[:space:]]+/, ""); print }' | sort -Vr | fzf)
pyenv uninstall $OLD_VERSION
pyenv install $NEW_VERSION
pyenv global $NEW_VERSION
pyenv rehash # idk if this is needed
pip install pipx
pipx ensurepath
echo "llm uv" | xargs -n 1 pipx reinstall