You don't have to install Node-RED globally, that is just the "simple" way it is described in the docs. It is a node.js app and can be installed and managed just as any other node.js app/microservice.
ls -l /var/log/node*shows -rw-r--r-- 1 root root 0 Jan 14 2024 /var/log/nodered-install.log -rw-r--r-- 1 root root 1668 Jan 13 2024 /var/log/nodered-install.log.1 -rw-r--r-- 1 root root 2073 Jun 21 2023 /var/log/nodered-install.log.2.gz
@TotallyInformation
Thank you for that hint, but I have no idea about Linux or how to deal with a microservice. And because I don't want to ruin the installation on my rpi4B I'm asking these questions.
I now assume that I will use the script for the upgrade. But first I will make a backup...