DeletedUser127 no, you're wrong and you can generalize
If you are doing something complicated, and don't want to be identified, you can route traffic in much more complex ways easily in Qubes. You'll have a unique fingerprint because of the connection latency and characteristics but some deanonymizing attacks are much less likely to work. Xen can be hacked and sometimes has exploits but they are rare, so it's secure, but you can isolate what you are doing in Qubes so much more easily.
This idea that Graphene is always better at everyrhing and all use cases is wrong. Graphene is a mobile OS and it's harder for anyone without a zero day exploit to hack it than regular mobile operating systems. It's defensive in a general way but it's not as good as Qubes for customizing things and running different types of programs. In Qubes if you wanted to daisy-chain whonix connections (which would be stupid possibly because you'll stand out) you can, if you want to work with a virus while working on other things you can (you could open up a disposable version of a mobile OS or clone it, load the virus, and safely do things in other programs at the same time as to see how the virus works). There are profiles that isolate in Graphene OS but you can't see many profiles at the same time.
You just aren't a Qubes user and don't know. If you know, you know. Qubes also, unlike GOS, is often a pain in the ass. Qubes is not smooth, upgrades can cause problems. Graphene OS and Qubes both have small teams but GOS updates are frequent and mostly completely problem free. Because Qubes works on all sort of hardware (but often fails), the new Qubes update can suddenly break your system. Many ethical hackers don't like Qubes because it's so much work to maintain and use. Something that will take two minutes to do in Kali may take 20 minutes in Qubes. Multiple that times many things and Qubes is often not worth it unless a person really loves technology or has extreme needs or is just intuitively good at technology or has extreme paranoia. It is 100x harder to use than GOS. GOS is easy, everything about it is easy, and it's harder to mess up GOS. The only hard part of GOS is a person's own mindset and getting past their own fears regarding installation. After installation, the only problem is for Apps that use Play Integrity API.
Some of the hardening doesn't even matter in Qubes because you use templates with very low attack surface or templates that spawn something temporarily so that if you are hacked, it's destroyed as soon as you are done anyway. You're more likely to get hacked in Qubes but it often matters less. Even with Qubes there are things you can't do because of limits of Xen which is why many tinkerers use things other than Qubes. There are lots of advanced use cases that can't be done in GOS out of the box, such as if you are trying to make and or compile a program.