Part of the problem is that - if you get COVID19 - you have less of a chance to get the flu.

Source?

This is an interesting idea though.
The notion that one flu-symptom inducing illness could reduce susceptibility to another flu-symptom inducing illness.

However, there's strong evidence that the flu vaccine increases susceptibility to coronavirus infections.

Influenza Vaccine: Military Study Shows 36% Higher Odds Of Coronavirus, 2017-2018

Also, numerous sources have identified whatever it is that passes for Covid-19 in samples that existed prior to 2020.

However, a peer reviewed journal article has never been published, which details the methodology used to conclusively isolate the virus from all other biological materials.

PCR is a manufacturing process. It's not actually a test.

They're using misusing PCR to manufacture a biological sample sausage, and then claiming that they can see a new and previously unidentified virus strain in the PCR sausage.

It's not science. It's hoax sausage.