I don't see an issue with the dating. I think many fail to realize the scope of how distantly related Romulus actually would be to Aeneas assuming the legend is true. Romulus and Remus would have been the 14th generation of Aeneas' line of descent based off their reported genealogy as can be seen in this infographic:
If we assume each generation was created every 30 years on average then the twins would be 420 years removed from Aeneas of Troy and Lavina, the daughter of the legendary King Latinus. If we assume Romulus and Remus were roughly 30 years of age when founding Rome in 753BC that would put their birth at somewhere around 783BC. 783BC + 420 years = 1203BC which is only 23 years of variance from the Troy layer VIIa destruction date of 1180 BC found in the bronze age collapse. Chronologically, the timeline is extremely plausible. That of course doesn't lend strong proof or evidence to whether this crossing of Aeneas into Italy did or did not happen, but it does support the plausibility of the generational dating. As far as what the Trojan refugees do for this time period, I'm not exactly sure what you're getting at here. Like anywhere else, towns and cities will be built and abandoned in varying contexts and locals will find novel ways to mingle and integrate into newly constructed proto-urban centers by a complex array of social relationships and heirarchies. We are talking about prehistoric Italy so little to none of it would've been recorded other than by word of mouth. To be clear I am not argueing that Aeneas definitevely was an ancestor of Romulus/Remus. I am simply argueing that I don't think it can really be disproven either right now or maybe ever.
I'm less familiar with Dardanus, though. I can't speak much on that aspect. One thing is very clear, however, and this is that the Romans very much bore a dual case of respect and disdain for their Greek counterparts within their writings. Greek populations were certainly favored above all other foreigners in the Roman political system with Roman colonies typically being built atop of those of Greek centers whenever possible. The Greeks were seen as civilized, scientifically advanced, literate and educated, along with the fact that their Gods were identified as identical or nearly identical to that of the Roman pantheon. These qualities and similarities, along with the prior expansions of the Greek world were certainly admired by the Romans and much of their philosophies, inventions and ways of life were certainly integrated into Italian society. That being said there was also a degree of seperation put forth by types like Cato the Elder, who expounded upon the rustic, hardworking, militant and disciplined virtues which he associated with the Italics in detriment to luxury, softness and indolance which were thought of as Greek and also more broadly eastern vices.
The takeaway from all of this is that the Romans were broadly intent on associating with but not identifying themselves with the Greek ethnocultural sphere. It seems apparant that they wanted to be understood as similar to but superior to the Greek world and the story of Aeneas and the fall of Troy reinforces this idea of furnished rivalry between similar nations that at one point in the past were much closer to one another. The Roman conquest of the Eastern Mediterranean fits indeed almost as a revenge story for the destruction of Troy. Whether Aeneas actually came to Italy and created a line which would ultimately found Rome can continue be debated but the story itself is convenient for the Roman narrative.