The official GrapheneOS Twitter account states the complete opposite on several occasions:
https://nitter.net/GrapheneOS/status/1692002070650335259#m
Many people have the misconception that they’re defeating the purpose of GrapheneOS by using privacy invasive apps but in fact the opposite is true. If you want to use those apps, then using GrapheneOS allows you to protect your privacy from them far better than another OS.
https://nitter.net/GrapheneOS/status/1728630943886270827#m
GrapheneOS arguably makes the biggest difference for someone who is going to be using a bunch of mainstream apps including very privacy invasive ones. They need features like Storage Scopes and Contact Scopes more.
https://nitter.net/GrapheneOS/status/1745532453215781151#m
You’ll substantially benefit from our privacy and security features without making significant changes to your apps. In fact, you’ll benefit more from features like Storage Scopes, Contact Scopes, Sensors toggle, etc. if you use a bunch of very privacy invasive apps.
There is one crucial detail that the article doesn’t mention: Find My iPhone must be enabled to enable SDP. That is to say, enabling Find My (along with biometric authentication) is a prerequisite for SDP.