All the points you mention are correct. However, I would argue that no society is perfectly moral. And the main reasons that Rome fell were not moral. They did include the lead poisoning you mention but that was out of ignorance and not a moral issue. The corruption and pride of certain emperors didn't help either, but that is the corruption of the few and nothing compared to the type of corruption we see in our society today which is not only of a self serving nature but of a satanic characteristic (what does it benefit the deep state to promote the transgender who are at best mentally ill, putting them in positions of power only serves to undermine society at no gain to anyone).

With the respect to abortion, be careful what sources you use. There has been a concerted effort by the pro-abortion groups to revise history in order to make it appear as if abortion has always been normal and widespread and it was the Christian fundamentalists who are the only ones who were ever against it. While Christians appose abortion, they are far from the only ones. Even as early as ancient Greece, there was an argument around it (NOT consensuses that it was ok as some would argue). While Plato and Aristotle were for eugenics and the killing of imperfect babies, Hippocrates (460-382 B.C.) opposed it and that opposition was in his original oath. Modern so-called historians are trying to re-write that part of history and the oath to suit their political views. In the end, the kingdoms of Greece and Rome (pre-empire at this point) did enact abortion on demand due to similar arguments that are made today. The argument was that if they don't offer it, women will take risks and do it themselves. However, there is no evidence that by the time of the Roman empire, this policy was any more widespread than it had been originally. In fact, with the Christianisation of Rome, while I cannot find any evidence of abortion being legally banned in Rome so it probably was not, any of the early Church fathers who spoke on the topic condemned it. As a result, with respect to abortion, the trend in Roman society at the time would have been against abortion, not for it and it's expansion. Here is a source about abortion in the ancient world and cites some of what I have stated here: https://www.ewtn.com/catholicism/library/brief-history-of-abortion-9589.

Furthermore, Rome wasn't promoting or marrying gay people. Rome wasn't changing the gender of children. They did have eunuch but that was a horrific form of slavery and was not intended to be an attack on nature or God even if it actually was. The eastern Roman empire, which survived, also had eunuchs and kept them into the middle ages so this can't be seen as the cause of the eastern one's collapse otherwise both empires would have fallen. Furthermore, they weren't castrating their population which would have caused a population collapse, just their male slaves.

With respect to pedophilia, even if Rome had a problem with it, were they trying to actively promote it as our society is doing now, granted still in the early stages. Because it is one thing to have a problem with something and a whole other thing to have the key intellectuals in your society promote some evil. The early Church fathers who I would argue were the key intellectuals for that period in Roman history were against any such thing just as they were against fornication, adultery, and any form of lust (something modern society promotes).

And regardless of internal morality, in the end, Rome fell due to external forces. They were broke due to constantly having to go to war with the barbarian tribes from the north and most historians consider the end of the western Roman empire to have occurred due to the last emperor being overthrown by the barbarians in 476 and not falling on their own due to internal force. Rome was really weak at that point, but mainly due to constant invasions and sacking by the barbarians and not due to any specific internal immorality.

Note that I'm referring only the the western Roman empire here. The eastern one is a different story. However, the very fact that the eastern one survived and the western one didn't also suggests my point as the two empires had very similar moral structures. If morality was the reason for collapse, then both should have collapsed. I would argue it was geography and perhaps with the eastern Empire seemingly having better leadership.

I would close this post by arguing that the current immorality we are seeing in our society has no historical equivalent. We have blown past Sodom and Gomorrah in terms or our depravity as a society. At least they weren't marrying men with men or women with women. And they certainly weren't messing with the gender of children even if they probably were molesting them if I had to guess. The worst part of it all is however that our society refuses to acknowledge sin as sin. In fact, it points to evil and says it's good and points to good and says it's evil. They only thing worse than sin is pretending sin is not sin because how do you come back from that. You can't fix a problem when you pretend it's not a problem. And ancient Rome was definitely not doing that. The early Church fathers in ancient Rome called sin out for what it was.