Looks like genomic sequencing is maintained at https://www.gisaid.org/, we can assume that sequencing is real and they did find a variant called Omicron.

The key to this puzzle might be by looking into the mutations that causes the variant to infect people. This is basically the ACE-2 binding area, which connects to the ACE-2 receptor and cause infection.

According to this paper

N501Y increases binding to the ACE2 receptor, which could increase transmission, and the combination of N501Y and Q498R may increase binding affinity even more; however, other substitutions in the Omicron spike protein are expected to decrease binding to ACE2. As such, receptor binding affinity needs to be assessed using the full spectrum of spike protein substitutions found in the Omicron variant.

Looks like there are individual mutations that looks like they can increase the binding affinity to ACE2 receptor, but as a whole, combined mutations actually decrease the affinity.

My guess is that its a natural evolution due to the evolutionary pressure by the vaccines. Reduced infection + increased spreading is perfectly suited for a mutation to become dominant, and at the same time create herd immunity in the population.

So perhaps its not a manufactured bioweapon, but rather the outcome of viral evolution.