We shouldn't install apps that use the Google Play Integrity or are closed-source in the first place. That's what I do.

The issues with GrapheneOS for me are:

1. They don't support rooting the OS. This is such a basic requirement for me. Why would I use an OS that doesn't let me do anything and everything with it?

2. They only support Google Pixel phones that don't have kill switches for the microphone, camera, radio and so on, as far as I know. GrapheneOS may be very secure, but nothing is 100% secure. Except cutting power to the mic. I'd be fine with physically removing the accelerometer and other sensors that can act as mics, even the mic itself. But newer phones are a bitch to open and close as they use glue instead of screws.

So right now I'm waiting for a Linux phone that's priced normally. I tried the PinePhone a couple of years ago, but it was an awful experience. Hopefully something comes soon. If not - I'll use my dumb phone.