With my Pixel 4a, I gave CalyxOS a try, but did not feel like I was ready to go for GrapheneOS, mostly because the website and the descriptions seemed a little too technical for me to bet on it with my daily driver. As I found out later on, GrapheneOS provided a more streamlined experience right from the installation.
When I got my new Pixel 8 last September, the reviews made me worry about the battery life I should expect from it. That motivated me to try GrapheneOS, and with a new phone in my hands, I could afford to experiment a bit.
Installation
Following the instructions, I first booted into Pixel's stock OS and updated the phone to the latest available firmware. Then, using the web USB installer was quite straightforward.
First boot
Once I booted into GrapheneOS, I found it to be quite polished, and I was easily able to locate GrapheneOS "App Store". With a great job done on the documentation, I was able to easily understand how I can get the Google Play store up and running on the my phone.
Once I installed a couple of apps, the phone started feeling more familiar to the stock Pixel OS.
eSIM Compatibility
An issue I faced in this phase - during my explorations with the network settings, I discovered the "eSIM compatibility" toggle. At this point I had an eSIM that I installed during setup on Pixel stock OS already installed and working. This toggle was obviously on at this point and I was able to get network reception and data connectivity. When I turned it off though, and tried to turn it on, I was not able to get data and network connection to work at all. No matter what I tried - multiple restarts, *#*#4636#*#* menu to enable disable DSDS, more restarts, all of these in various sequences, I was unable to make eSIM work again. I gave up finally and had to go back to Pixel OS, check and enable my eSIM, and then reinstall GrapheneOS from beginning. During everyday use, I still remind myself never to turn off the "eSIM compatibility" toggle.
App compatibility
Excellent work has been done by the GrapheneOS team to ensure a sandboxed Google Play can make most apps work. However, as far as I understand, Google has started limiting alternate OSs and this makes the Play Protect certification an important aspect for app compatibility. Because of this, or other reasons, I have faced problems with the following apps on this OS:
1. Tata Neu: For some reason flags my device to say "the environment is not secure".
2. Paytm: As the app detects that the Webview implementation is something called Vanadium Webview, it refuses to let me login.
3. DigiYatra: Used to work, but with some update, has flagged my device to be "not compatible"
4. Find My Device: I understand that since the sandboxed Google play implementation does not give infinite rights to Google play services, this app is not able to locate my phone through the find my network. This makes me dread getting my phone stolen or losing it.
5. ICICI iMobile: Works well, except for the tap and pay feature - it never finishes loading.
Will update this list with more as I discover other incompatible apps.