That doesn’t feel very de-Googled, when it’s using an OS that was built by Google on hardware made by Google. Sure it removes their services and adds some security/privacy, but it still adds to Google’s power by giving marketshare to both their mobile OS and mobile hardware.

It's uniquely hard to get rid of Android (when you don't consider iOS as an option, because possibly the remedy would be worse than the issue). A degoogled Android is already a good step.

I'm as little reliant on proprietary services as possible and I'll jump to Linux mobile (having used a pinephone for one year as my main phone, I know it'll be comfortable for me) when a convincing phone that's not very expensive given the outdated hardware it has and that doesn't rely on an Android base can run it smoothly enough, but that phone doesn't exist yet.

Alternatives include not having a smartphone but the network effect and the expectations on you having one are quite strong.

The Fairphone 5 I have is very close to run PostmarketOS well, I have hope but for now few but critical features are missing.