The existing script leaves 10 or 12 if they are there (unless it is the apt installed old version of 10 :-)... If there is no node.js at all it will install 12.
So if the node updates have worked you should be on node10 plus latest node-red plus latest versions of all extra nodes... (which indeed as Colin points out may break some - so yeah need to think about that - as I said this is mainly me thinking about Node-RED v2 - so maybe I need a different script so it obviously different etc)
If you want to jump to node 14 then if you are on Pi3 or 4 then (for now) the way is to edit your /etc/apt/sources.list.d/nodesource.list file and change node_10.x to node_14.x - then use the use the usual sudo apt update && sudo apt full-upgrade to get node14 ... and then finally in the .node-red folder - run npm rebuild
If you are on arm6 (Pi0,1,2) then it's a bit more involved as we need to hack the script.
