I guess we'll just agree to disagree. I find Stellaris to be pretty darn good. But yes, it does have issues, but nowhere near to the extent you're suffering. Maybe I'm just more tolerant/clueless.
I just find it extremely nice to have a 4X that doesn't bog down into a microfest with 10 hour long turns by the endgame. That said, the sector system really needs an overhaul, as it's borderline broken for all the good things it does.
I also miss a couple of diplomacy option, such as demanding the release of a system without war, outright CONQUERING a system (it goes back to them if they surrender unless they agree to give it to you) and the ability to really pressure a weaker empire. It feels like vassals really don't do anything unless you go to war, where they will support you. But what are they otherwise? They're just a bother.