Perhaps I was not clear. A virus can't "adapt" to not being physically presented to its potential host. It can't "adapt" to "being blocked by a mask" or "the person I infected intelligently self-isolating and thus I can't spread any farther". Even if you could hypothetically draw out genetic changes that would permit it, it would require substantial changes to evolve all at once.

Not really, no. There is a 99.999% chance that the virus was just as infective if not more in bats or pangolins or whatever, and simply adapted to humans.

These mutations are the virus finishing its adaptation to humans. It will eventually end up at a local maxima, just like, say, measles did.

It most likely jumped the species barrier.