I think it’s because JIT instructions are disabled on GrapheneOS for some things as an exploit protection, including patching, writing, and installing apps. I clocked it in at about 15 minutes to update Morphe’d Youtube last week. System updates too, there’s an app optimisation pass every reboot after GrapheneOS updates.

More as an FYI, I’m not complaining exactly. I’m just not sure why the ReVanced manager did the job faster.