I do think 70s devils minion adds a whole layer to Daniel and Armand's relationship that we're not really taking into account enough bc while it does kind of technically happen in canon (that they break up and then get back together) we never actually get to SEE them when they're back together and so its not really taken into consideration for their dynamic.
But like Armand is someone who has for his entire life been another person's possession, who has defined himself as a person that people Have instead of Love. And what the Queen of the Damned chapter shows is Daniel Molloy as someone who Armand wanted to possess and who wanted to be possessed by Armand. Armand has never owned anything in his entire 500 year life and so he NEEDS to own Daniel, he needs to have just this ONE THING to himself after all this time. And Daniel for his part is very into being so consumed by another person. For a time, Daniel is exactly what Armand needs. Here is a person who cannot hurt him, who wants to belong to him, who he can finally assert authority over and in doing so assert his own independence. Nobody in Armand's life has ever been truly HIS in the way that Daniel is.
But the longer theyre together the less urgent the need to possess and control is, and the more Armand is able to love Daniel selflessly, the more they come into conflict because Daniel still WANTS that level of obsession. Their breakup in the books is inevitable because their relationship was built on impulses that, while important stages in their growth, over time became unhealthy. Daniel needs to get out of his cycle of addiction and Armand needs to grow past needing to possess people to believing they'll stay of their own free will. So they need to break up.
BUT unlike in the books where Armand's resolve ultimately fails him and he turns Daniel anyways, cementing the both of them into both of their unhealthiest habits, show Armand manages to work through his issues to the next stage of his growth: that he needs to let Daniel go. And he does! He lets Daniel go and he bears the burden of their relationship alone for 50 years so that Daniel could not only have a human life but also develop as a person in a way he never could have if he stayed with Armand. Show Daniel is a different man from 70s/book Daniel. He knows who he is. Even though he's falling back into old patterns now that he's a vampire he's still been through this cycle a few times and hes stronger now than he would have been if he was turned when he was 30.
I think, assuming devils minion did happen in the 70s, the present Daniel/Armand dynamic will be different from what we're expecting because they've finally grown enough as people so that they can come together on equal footing which is really important bc Armand has never been someone's equal in a relationship before! This is new territory for him! So I think their relationship has potential for development of both of them as characters to places they never got to go in the books. Please note that this is NOT me saying they will have a perfectly well adjusted healthy relationship I just think that this is the next step past their old dynamic and probably will be more dangerous for other people than it is for them which is always a win.