I usually use nvm to manage node.js versions for projects, but there are not official binaries for the ARM V6 chip in a Raspberry Pi Zero for node versions 12 and higher. The source is still available, and so if you try
nvm install 14.17.4 nvm will attempt to compile from source, which on a Raspberry Pi zero will take a long, long, long time (and probably fail).
Fortunately node.js provides "unofficial builds" of newer node versions for ARM v6 at unofficial-builds.nodejs.org.
You can use these binaries with nvm by providing a url to use instead of the default node.js binaries url:
NVM_NODEJS_ORG_MIRROR=https://unofficial-builds.nodejs.org/download/release nvm install 14