For me a big difference would be not sending my data to Google. Even Lineage OS still sends a bunch of data to Google all the time. If you’re not careful it sends location data, DNS queries, etc.
I want a mobile OS that gives me complete control over my personal data.
At that point what’s the difference between this and Android
How many major phones can you buy with AOSP installed by default today?
How much development gets done on AOSP that isn't at least heavily influenced by the direction Google takes?
Does AOSP provide comprehensive privacy and security options for users but still freely connect with other devices and services using open standards?
Obviously if you're going to be Linux-based and if we're assuming some degree of compatibility with Android APIs to make porting apps easy then there is going to be common ground with AOSP, but I don't think that makes it the only or necessarily the best option.
But that’s just the issue we already have most of this freedom available yet hardly anyone takes advantage of it.
Heck how many people do you think install SailFish on their phones? You can buy pretty decent Android phones with AOSP and even SailFishOS builds yet people aren’t taking advantage of that in any particular manner.
If almost no one uses it, even amongst those who claim they want that freedom why will build a business model around it?
I want a mobile OS that gives me complete control over my personal data.