Covid won't change into the flu, that's like assuming a chicken might evolve into it's ancestors species or humans will evolve into apes. Evolution goes forward, not (or rarely) backwards.
It's a completely new species that, up until 2019, did not exist in the human population.
This sort of evolution happens frequently when people are in close contact with animals. Hence the reason European disease wiped out native populations but not the reverse. Also, a direct example of human evolution.
I think this is where we differ. That obnoxious spiky little ball we all now know as coronavirus(es) existed in both humans and bats long before making the "jump". Ignoring the possibility that humans are directly responsible for the new host capabilities, it's not like we watched influenza slowly morph into a coronavirus and cause a new form of havoc. All we saw was an existing "species" that had mutations inside the bounds of its genetic code that enabled it to survive elsewhere.
You might find that pondering the existence of "ring species" proves enlightening. It turns out that "species" isn't even a well defined concept when you look closely enough.
https://en.wikipedia.org/wiki/Ring_species
(Also, you needn't capitalize "evolution". It's not a god :))
I struggle with the speciation aspect of Evolution. Not hard to empirically verify in-species adaptations, but I'm still waiting to see coronavirus turn into influenza (etc)