Delta was caused by mass vaccination in India, it was called the India variant at first, remember? Then they changed it to Delta because India used Ivermectin to destroy the virus completely, and the world didn't want people noticing that. I think omicron variation was either also engineered and released on purpose, or it's the natural progression that all viruses have toward becoming endemic (spread to almost everyone, with almost no symptoms). This was expected, and predicted by many of us outside the paid state media :)
The "it has never been isolated" thing doesn't carry any weight with me. 99.7% of people saying that don't know what it means, they just heard somebody else say it.