Are you sure you're looking at the native share sheet? It scrolls vertically, at least on Pixel on Android 11.

There's some intent: links on https://paul.kinlan.me/sharing-natively-on-android-from-the-... that you can use to trigger it. The first one there doesn't work for me, but the second one does.

     intent:#Intent;action=android.intent.action.SEND;type=text/plain;end