JohnnyDavis If your goal is to have as little Google code on your phone as possible, but you are ok with Google reading mail sent to your GMail account, then using FairEmail (or any other e-mail client) instead of Google's e-mail client will reduce the amount of Google code on your phone.
It's not clear offhand which privacy concerns would be posed in particular by running Google's mail client, though. If you're concerned about Google being actively malicious, Maps would be equally plausible as a vector. And using Maps sort of inherently provides Google with information about your location.
I guess I'm saying it may be productive to list precisely which things you want to avoid (Google scanning your e-mail; Google knowing where you are) and then consider mitigation strategies. For example, if you want to access GMail from your phone but you don't want them to know where you are when you do so, a VPN may be appropriate.