If I'm starting a new project in Ktor for learning purposes should I use Ktor-2.0?

ymmv, but i always try to stick with the latest stable version when I try out something new.

We recommend using Ktor 2.0.0 because you get used to the new API faster and because it will be released soon.

Last time I checked a lot of plugins like auth were not available yet for 2.0.0

What do you mean that plugins aren't available?

Nvm, it seems to be available E.g. https://mvnrepository.com/artifact/io.ktor/ktor-server-auth-jwt

For example Koin does not work with Ktor 2.0. Many of the learning resources recommend using Koin for dependency injection. This definitely makes it difficult to follow tutorials.