Is there an apexcharts app extension? If yes, you need to change the command to the org it belongs to, because there isn’t an official app extension, which is what you are trying to install.
If there isn’t an unofficial app extension out there, then have a look at this boot file.
https://github.com/patrickmonteiro/quasar-apexcharts/blob/master/src/boot/apex.js
That whole repo/ project is a demo of apexcharts with Quasar.
Scott