A virus always mutates and a coronavirus in particular. The vaxx is speeding up the mutations because it is narrowly targeted on a small set of proteins. All the virus does is replicate with small changes in it's protein profile until one manages to evade the artificial antibodies created by the vaxx.
You have to be careful when discussing a virus because it's not alive. They don't have a thought process to spur itself to survive against a challenge, whether natural immune response or artificial antibodies. As a virus copies itself in cells, some of the copies are "flawed." Most of the time, the flawed copies are destroyed by the immune system because it sees them as foreign material. The vaxx has limited the range of imperfect copies that are recognized as needing destruction. The copies that aren't destroyed become new dominant strains.
I think the "scary" variants are emerging from places where the vaxx phase 2 trials were conducted. The vaxx phase 3 trial, for which millions have become volunteer guinea pigs, will produce even more variants that can evade the vaxx. Those variants should be less deadly, but don't count on government to act accordingly.