It can be as private as Graphene OS if no Google services are installed. Difference is that the former lacks a strong security model because of its unlocked bootloader.
If your threat model involves:
- Counter-forensics
- Sensitive professional work
- Malware exposure
You should consider installing Graphene OS instead. If you want the camera to work better, you can install GCam (Google’s default camera app) and revoke its network permissions.
Otherwise, Lineage OS is a great option for a secondary device, not a primary one.