Yes, Qt (and Felgo) have a custom rendering, so everything is drawn by the Qt application based on the Qt/Felgo controls and layout in your QML UI. The tech stack is thus a bit different, so I am not sure if the Android UiAutomator is usable in some way.
Squish is the Qt solution for UI testing. There’s some information on using Squish for Android here: https://doc.qt.io/squish/installing-squish-for-android.html
Unfortunately I also do not have any first-hand experience here.
Best,
Günther