This an egregious misrepresentation of the findings in the cited paper [1]. Here is the line the author was likely referencing:

> Therefore, if we track a single lineage of virions from the time they started replicating in the body until the end of the infection, this lineage would accumulate in the range of 0.1 to 1 mutations on average across its entire genome

The OP completely misses the forest for the trees, so to speak:

> Because the SARS-CoV-2 genome is 30,000 nucleotides long, the 105 to 108 mutations across all of the virions produced over the course of a single infection probably cover every possible single nucleotide substitution (Fig. 3A). They even cover a significant fraction of the possible pairs of single nucleotide substitutions.

> the estimated number of mutations generated daily (105 to 106 mutations per day) likely exceeds the total number of possible single nucleotide substitutions to the SARS-CoV-2 genome (≈105 substitutions) assuming 0.3 million to 3 million new cases a day worldwide. As such, our estimates imply that every single base mutation is being generated de novo and transmitted to a new SARS-CoV-2 host, somewhere in the world, every day. [1]

It's great that these articles cite sources for their claims, but keep in mind that the authors are not necessarily experts (or even remotely qualified) in the subject matter. They are liable to misinterpret and misrepresent the scientific literature they use to support their narrative.

[1] The total number and mass of SARS-CoV-2 virions https://www.pnas.org/content/118/25/e2024815118#F3