You make it sound as if the virus is a self aware entity that chooses not to mutate it's s-protein due to what you refer to as it's "needs". I'm not even going to respond to that...

Your "guarantee" that no big changes to the S protein can happen without losing functionality or doing something different is exactly what the abstract I linked to mentions. It takes all of 30 seconds to read it:

We observed intrapersonal variation and 6 different mutations in the spike glycoprotein (S protein), including 2 different SNVs that led to the same missense mutation. Therefore, we provide direct evidence that the SARS-CoV-2 has acquired mutations capable of substantially changing its pathogenicity.

How many studies and scientists have to point out the obvious, a traditional vaccine isn't going to work on this virus, before we start looking towards high tech solutions that will unfortunately disrupt the capital of the ultra rich?