Something I have found worthwhile has been listening to the UBports podcast over the last 6 months or so. They really do seem to be 'getting it' faster than most re: what's left to be done. That's partly because they're in the rather unique position of coming from a place of having the Android kernel (which isn't just a vanilla Linux kernel) do a lot of things for them (i.e. UBports on Android phones) and now that they're running on bare metal (i.e. UBports on Pinephone) with (mostly) the same code base they are able to see 'oh, yeah... the kernel and/or apps need to be able to do Y' in order to replicate the functionality they get on Android phones.
Just curious, what corporate backing are you referring to? I hadn't heard that before.