A group of archeologists discover by accident an abandoned terraforming complex far below the chicxulub crater,But this is just the begin,The archeologists recover an alien artifact that scientists call ¨the seed¨,This big metallic sphere contains strange genetic material that shows 90 % similarities to human DNA and other species of mammals,There is no doubt,Someone created us for some reason,Killed the dinosaurs and terraformed earth long time ago,The archeologists decide to make public this information before the goverments stop them,The world is shocked by the information,But how would major religions react and its fanatics?
I would say big religions/sects would eventually adjust rather easily to the new facts, as they've always done. For example, when the Catholic Church was faced with the theory of evolution by natural selection, its first reaction was doubt and denial. Later the theologians got to work, while Catholics at large of course also absorbed and played with the fact of evolution, and by the last part of the 20th century it was already possible for the Pope to say that evolution was fine by him, as long as God had invisibly intervened somewhere along the line to make humans into spiritual beings. There are of course conservative Catholics who, like many Evangelicals, do not accept evolution, but they're fewer and fewer.
I suspect the new findings about humans origins could be disputed and denied within smaller religious sects, especially those that find themselves in close competition with others (this is, I think, one of the postulated reasons why religious freedom in the United States gave rise to so many fundamentalist/literalist movements). If you're part of a small religious group, you need to differentiate yourself from the rest and from the culture at large, and one of the things you can do (or your leaders can promote) is denying certain things that most other people accept, such as evolution or the age of the Earth or the efficacy of vaccines or (not scientific fact, but moral consensus) equal rights for men and women or the immorality of slavery. It's not really important that you actually believe that: your refusal to accept the consensus is a form of virtue signalling.
So I think it would be interesting for you to focus on the immediate reaction to the discovery of our extraterrestrial origin, but the process as a whole (from shock to denial to accomodation to acceptance, cut short for some factions) would be fascinating to play with. Religions being so varied, you can imagine almost anything.
Religious fanatics would simply claim that "here is the proof our holy books are correct and some higher power (I don't use any specific god name for the sake of generality) created us".
Something similar is already happening in India, where some local religious authority claims that major findings of 20th century science are in reality described in their holy books and were only stolen by British Empire.