Thanks for asking.
Question 1. Aside from unreal fears of demons, hell, and eternal punishment, the only way I think it affected me negatively was with respect to morality. Religions tend to teach what to think morally (follow these rules), rather than how to think morally (reduce emotional and physical suffering). The Golden Rule, mentioned in other cultures independently of Christianity, seems to come up short in this respect because it is susceptible to treating someone how you think you should be treated in the same situation. The Golden Rule is a good approximation, but it falls short.
Question 2. I was raised Catholic, Church and Sunday School every Sunday, and reminders of biblical teachings throughout the week, but not formal.
Question 3. I don't think anyone you ask will have a single answer, and the way the question is worded would lead to that conclusion. Different people have different thoughts about their religions at different times and in different orders from one another, so there really is no one big "gotcha." Collectively, the things that led me to conclude that Christianity is man-made are:
Immoral acts committed by the biblical god and it's followers, things that neither I nor you (hopefully) would ever commit. Nothing all-moral, all-loving, all-knowing can ever, ever have a foundation of immorality. That makes us, flawed as we are, more moral than such a being and it prophets - how can that be? It an be if it is man-made.
Moral failings of the Ten Commandments. Coveting was important enough to get a commandment, but not rape? Not slavery? Not child abuse? Not incest? And with respect to coveting, coveting of your neighbor's wife is a problem, but not your neighbor's husband? That shows these rules were written by men for men.
Moral failings of Jesus. Jesus never spoke against slavery, and even used it in his teachings. Slavery was quite normal to him. Yet, we, as flawed humans, saw that it was wrong, passed laws against it, and in the U.S., fought a war to end it. The Bible even instructs how to conduct certain matters pertaining to slavery, instead of denouncing it. Supporting slavery is a major moral failing of Jesus and the Bible.
Misogyny. Women shall be silent. Women shall be submissive. In war, young women and girls shall be kept, while all others are slaughtered. Yet we, as flawed humans, saw this was wrong, and passed laws granting and protecting rights for women. Like slavery, the Bible was used to justify discrimination against women.
Although Matthew tells us of Herod killing all the young boys in and around Bethlehem, there is not one single account of this by any other historians of the time. Bad news travels fast, and yet, not even a word of this by the Romans, Greeks, and scholars such as Josephus? This is a fiction. We also know that the story of Noah's Ark came from ancient Babylon; the Babylonians conquered ancient Judea, marched thousands of prisoners to Babylon, and there they were exposed to the Babylonian myths and legends, in this case, Gilgamesh. The Judeans incorporated this into their culture and when the eventually left Babylon, brought it back and incorporated it into the OT. It is fiction as well. These (and other stories) beg the question of how much more of the Bible is either fiction or borrowed, again showing it is man made.
The constant evolution of the meaning of supposedly sacred scripture. If you ask the people who voted on what went into the Bible, and the early Christians who practiced it, you would find that it was quite accepted quite literally. Now, thanks to scholarly research and archaeology of cultures in the area, people now take parts of the Bible to be allegorical, metaphorical, poetic, etc. In other words, not true, yet these things were put in by the people who created the Bible because they were believed to be true. We can look at every religion and see how they have evolved over time to continue to exist and thrive, including Christianity.
No evidence that demons and demonic possession are real, despite numerous biblical accounts as well as accounts throughout history. Thanks to modern medicine, we now know this is due to brain disorders,schizophrenia and multiple personality disorder, and can treat them with medicines.
Although we hear of medical miracles through prayer all the time, not once has anyone ever regrown so much as a lost little toe, finger, ear, eye. Never. This shows that prayer does not work, and that medical miracles are not true.
Scientific claims made by the Bible that are clearly wrong. Yet another area of errancy.
Despite all the accounts of appearance of the biblical god, angels, demons, etc., in the Bible and throughout the centuries, we have no proof of such claimed events in modern times. As a matter of fact, we have no proof of any such beings from any of the thousands of religions that currently exist on earth.
The idea of an omnipotent and all-loving, all-moral being eternally punishing anyone is morally reprehensible. People are born into circumstances, without knowledge of anything else, subject to the effects of their poverty, ignorance, and for this they are punished forever? Is this what you would do as an omnipotent being? My strong belief is "no," as it is for everyone. People do terrible things because either they were born with wrongly wired brains (think psychopaths, sociopaths), or their otherwise healthy minds are loaded with horrible parental teaching. Morally, I cannot fault anyone for either of these two things (though we must protect ourselves against them). So, eternal punishment is another failing for a supposedly all-loving, moral, and knowing being.
So, why do religions exist and thrive? They do one thing very, very well - they provide stress relief from life's problems and challenges: one can pray to one's god believing that these thoughts are heard and on occasion resolved, they give unproven hope for an escape from death not only for the believer but for everyone (and pets) the believer loves, they give an unproven ultimate justice for those crimes that go unpunished while people are alive, the allow people to gather regularly in service that provides both socialization and reinforcement/support. All of these things provide stress relief. But most of all, Christianity (and other religions) teaches that this life is temporary, and therefore so are its problems. And although that makes everyone feel better, that's actually a huge problem because we tend to take society's problems of overpopulation, resource depletion, pollution, extinction of animals, etc., less seriously than we should, and therefore assigning less effort and resources that these problems deserve.
Question 4. Do I find solace? What I find is that I am able to see the world for all that it truly is, beauties and tragedies, and knowing that they are real, that I can enjoy the beauty and work to prevent the tragedy. We can see where others have done this. I personally believe that while we are alive we have a duty to help ease each other's suffering, to lighten other's burdens. Leaving religious morality behind (follow these rules) and adhering to human morality (reduce emotional and physical suffering) has allowed me to love and care for more of humanity. So, yes, I find great solace in my non-belief.