PCR only detects nucleic acid.
Whether it is a positive or negative result depends on the settings dialed in by the machine technician.
Whether the nucleic acid is the result of bacteria, Type A flu, Covid, Delta, Omicron or other viruses is anyone's guess… no one can say definitively.
The people who are saying "definitely" it is Covid or a Variant
have a financial and totalitarian political agenda
because they want you dead or under their total control as a slave.