No, i'm well aware that there will be millions of individual viruses replicating inside a person, and that it happens in a matter of days.Do you think a virus takes 9 months pregnancy to give birth to its similar?
Once attached to a host, the process is not slow and to your thinking, vaccinated people can also be hosts of this virus.
Draw your own conclusions.
The likelihood of a dangerous mutation occurring in each replication is incredibly small, but when you consider the number of replications in a carrier and the number of carriers, the likelihood of a successful dangerous mutation occurring goes up. The more carriers with a higher viral load, the higher the chance of a viable dangerous mutation occurring and being transmitted.
Vaccinated people's immune systems fight the virus much more quickly and massively reduces the number of replications, which massively reduces the likelihood of a dangerous mutation occurring.
Do you think this isn't a dangerous virus?