It stands to reason newer models receive more updates as they have more problems than a mature product, when i got my Nokia 8 it felt like the updates never stopped. However to allude that the Nokia 8 has been forgotten is ludicrous, Nokia cannot fix what Google have broken and i suspect all the things you mention that are in relation to the OS and not the hardware will be rectified when Google fix the bugs.
That said my screen never freezes and my notifications work just fine, i can't comment on dots as i use Nova Launcher and i would prefer not to see them anyway, i cant see the point in them.
I don't have any of those issues you mentioned so before accusing the phone of being the issue, how about a factory reset to see if it actually IS the phone or whether it's a software issue. I'm sure that 100% of those issues are caused by software!!!
As for updates I don't see the problem, newer phones get updated first usually because they are the ones with the most software issues to fix, it's no good leaving new phones with issues to concentrate on fixing issues with phones that have minor issues instead.