I think that the no-virus group is caught in circular reasoning.
The same people with the same arguments referring to old experiments.
And assuming a simplified model of biology.

Viruses can be seen, stored and tracked. They can be observed in many ways.
But one need to use some tricks, because they are so small and can fall apart easily.
They need to be stored with living cells that are not fighting the viruses.

There are also prion diseases that are caused by much smaller biological components, wrong folded proteins.
And bad proteins are also present in ALS.
These proteins are even less visible.

From scientific point of view, the problem is that there is room for anyone to insert bias into the research. And due to the market of ideas, we only see promotion of the most extreme sides. So due to Big Pharma, there is also a bias in the virology that causes exaggeration of the harm. And there is a clear bias from Lanka to claim that there are no viruses.

The real scientific discussion is about how the bias affects the conclusions.
How viruses work exactly and how they only affect some people and not others.
The same with any disease.

There was research on how our psychological state causes change to our molecular messages.
And the message system is hijacked by viruses. So it also depends very much on your emotions and living conditions.

Our body is optimized for living in nature. This means that hunger and weather can even make us stronger.
Hunger can help your body to dispose of cancer and other "broken" cells.
And exposure to germs and other people makes us stronger.