One more question: What principles would help establish how much dominance seeking behavior is enough to break the relationship or in some other way cause more damage than it's worth

Yes, that part is hard, even on a micro scale. I have been frequently surprised that I underestimate how much dominance seeking would be optimal. I attribute this to mind-projection. ie "This means she would prefer me to do that? Wow. I'd never take that shit if it was directed at me. Hmm... I'm going do that for her benefit and be sure not to send any signal that I am doing it for compliance. It's actually kind of fun."

(Here I do mean actual unambiguous messages - verbal or through blatantly obvious social signalling by the partner. I don't mean just "some source says that's what women want".)

considering that part of dominance is ignoring feedback that it's unwelcome?

Fortunately we can choose which dominance seeking behaviors to accept and reject at the level of individual behavioral trait. We could also, if it was necessary for a particular relationship, play the role of someone who is ignoring feedback but actually absorb everything and process it in order to form the most useful model of how to navigate the relationship optimally. On the flip side we can signal and screen to avoid dominance seeking behaviors that we particularly don't want and seek out and naturally reward those that we do want.

"Deliberately faking social signals"? But, but, that barely makes any sense. They are signals. You give the best ones you can. Everybody else knows that you are trying to give the best signals that you can and so can make conclusions about your ability to send signals and also what other signals you will most likely give to them and others in the future. That is more or less what socializing is. I suppose blatant lies in a context where lying isn't appropriate and elaborate creation of false high status identities could be qualify - but in those case I would probably use a more specific description.

PUAs have trouble grasping that there is a difference between appearance and reality, which is ironic in some ways. It's an implicit part of their doctrine that if you can pass yourself off as an "alpha" that you really are an "alpha", in the sense of being the kind of person that women really do want to mate with.

However it seems obvious to me that the whole PUA strategy is to spoof their external signals in a way they hope will fool women into drawing incorrect conclusions about what is actually going on within the PUA's mind and what characteristics the PUA is actually bringing to the relationship table. It's a way for socially awkward nerds to believe they are camouflaging themselves as rough, tough, confident super-studs and helping themselves to reproductive opportunities while so camouflaged.

They excuse this moral failing by saying "Everybody else is doing it, hence it's okay for me to do it only more so".

However it's well-established in general societal morals that obtaining sex by deception is a form of non-violent rape. If you're having sex with someone knowing that they are ignorant of relevant facts which if they knew them would stop them having sex with you, then you are not having sex with their free and informed consent.

The fact that someone is a PUA using specific PUA techniques to misrepresent their real mind-state seems to me like highly relevant information in relationship decision-making.

A third would be "could the majority of humans have a romantic relationship without dominance-seeking behavior?" and the fourth : "would most people find romantic relationships anywhere near as satisfying without dominance-seeking behavior?" (My money is on the "No"s.)

Is there proper scientific evidence for this? If not do you acknowledge that this is at least potentially a moral excuse of the same form as "Everyone else is doing it, so it's okay for me to do it"?

I suspect it would actually turn out that correctly socialised people would prefer and flourish more completely in relationships which are free of dominance games, and I think my naive folk-psychological guesswork is just as good as yours.