I have this installed on the odroid N2 and would like to set up a web server for a differnet purpose.
Can I just log in and start installing new software, or would I need to do a fresh install of a different OS and then install kodi manually?
Docker could probably cover what you want, its in coreelec addons and add linuxserver.io repository, which is there somewhere and you’ll get an idea of what you can install out the box. Docker has many more images than just those, it’s not that complicated to use.
Docker addon plus LinuxServer Swag would get you a pretty standard webserver (e.g. for reverse proxying or for serving a basic static site).