Had same issues.
My current solution:
Phone: Pixel 6 Pro (Android 13 OS)
1) Delete app
2) Remove Bike from phone's Bluetooth device list and phone from Bike's Bluetooth device list
3) Power off phone and bike
4) Restart phone
5) Download app but DO NOT OPEN
6) Go to system settings (App Info) for the app
7) Grant app all permissions
8) Turn off "Pause app activity if unused"
9) Now open up app and login
10) Download " LightBlue" from Play store
11) Turn on bike
12) Use said Bluetooth app just downloaded to connect to bike. (It may take a couple of times)
Unfortunate that such hacks have to be used. But working fine for now. Before I couldn't even get the Livewire app to open.
As for Bluetooth, I could never keep a connection. Only downside to using the Bluetooth app, is that I have to reconnect through the app every time I start the bike. Doesn't automatically sync up.