There are 3 ways to use quasar. I don’t think this is one of them. It would be awesome if it was that easy to just import a random component like q-table in an existing project. For the why it doesn’t work like this. My guess is that q-table depends on other quasar code.
https://quasar.dev/start/pick-quasar-flavour
I think the UMD route is the way to go for you, or rebuilt with Q-cli.