I don't know what I'm doing wrong. I've installed obtainium but when I search amethyst nostr it displays unauthorized
This is your periodic reminder to install Amethyst (and all other Nostr clients) through Obtainium instead of Google's PlayStore.
You not only receive faster updates (the PlayStore is currently 4 versions behind) but you also start the process of freeing yourself from your invisible digital overlords.
Just follow this video: https://cdn.satellite.earth/2bd7e308c1797d64fca09b1d61e9bde24c68dd45e501c7383eff1e85392df11f.mp4
Discussion
Did you copy/paste the Amethyst github repo? If not obtanium is a tool to get updates for apps from locations but not a traditional market so you can't search for things.
Try pasting this in if you didn't already try it: