Tldr: GrapheneOS for Normie apps, Jolla for FOSS exclusive phone.

IMO take GrapheneOS, because when it comes to security, there is basically no competition. You need the security if you want to use normie proprietary apps. There is just so much cancer in that ecosystem, it is unbelievable, furthermore, you're handing the malware an unbelievably capable sensor platform with centimetre accurate positioning systems, motion sensors which can gauge your weight, age and gender, microphones and cameras. You NEED the protection that GrapheneOS gives you.

On the other hand, if you only want to use FOSS on your phone, then SailfishOS is also a good choice. But due to security, it is highly recommended that you stay away from normie apps.