Don’t believe that at all. Omicron is not a derivation of the first Alpha version. Its got half of the two cleaves. It did not go to some African HIV patient and stay there for 18 months before finding a second host. Its a second lab leak. Its a precursor. And its acting the part of a live vaccine.
Your story would be a child of Alpha that leaked, not the first Alpha patient. But rather the patient before him. Who would be a HIV lab worker. Boy is that a bad job. Then that guy would have to go to Africa and maybe 14 months later give the virus to another guy, who spreads it all around southern Africa. Hard to imagine. Easier to imagine China or America is trying to save millions of people but does not want self incrimination. So they let their live vaccine go in a place that has little advanced systems for tracking or detecting a virus. To give it a nice head start. Eventually South Africa spots it but only after it has gone through several African countries.
Remember the lab has the virus before the cleave and any partial versions. So it already has a vaccine. But to let that version go in China would be admitting the lab leak to the world. So they need to give it to someone else and let it find its way back to China or America.
Agree about that being a bad job, lol!
The theory that it evolved in a HIV+ positive patient (or other chronic illness such as a TB sufferer) seems the most plausible to me:
https://www.nature.com/articles/d41586-022-00215-2
According to this, it did evolve from a child of Alpha:
“...evolutionary virologists estimate its closest-known genetic ancestor probably dates back to more than a year ago, some time after mid-2020”
You may disagree, which is your prerogative.
It’s still somewhat of a puzzle, I’ll grant.