I haven’t got as many miles in mine yet, weather has been so crappy this spring, and so far my experience is quite similar. I have the hydraulic brake EDS TX which I have on my gravel bike mixed with GRX cranks and 11-34 11s cassette.
It took a few attempts to get the shifting dialed in and yeah the app needs work, or at least how the initial setup flow needs better explaining. Once you get past that it seems to be working as expected.
An alternate app (web based) is at https://dreds.jeckyll.net Just note that needs webBLE support which works natively on Android with Chrome but iOS uses need a webBLE enabled browser such as BLE Link because iOS doesn’t natively support web Bluetooth.