Get a phone that runs GrapheneOS (second-hand Pixel 7 or 8 will do fine). Run apps that do not require it without Google Play Services and run apps that do require Google Play Services with the sandboxed Google Play Services. That will constrain the data that can be collected a lot.

(Yes, there will still be issues if you use apps that require Google's remote attestation, but at least in Europe, many banks etc. do not require it.)