Mutations can go either way. They can make a pathogen more virulent or less virulent. So far it appears that those who become ill with the omicron variant are incurring only a mild illness. that of course can change. what is yet to be sen is to what extent that the immunity developed in these patients protects against the more virulent strains of COVID. Often that is what happens and how pandemics naturally end. Yet it is still far to early to know what will ultimately happen with omicron.
Also the nature of the total immune response to COVID infections is not understood. People are preoccupied with antibodies and titers but know almost nothing about T cell immunity and other immune factors in these patients. Also there has been almost nothing done to identify those who are genetically susceptible or genetically resistant to this pathogen.
Variations in Covid strains are not mutations they are adaptations. Mutations can go both ways but a mutation that can survive has the odds stacked against it.
Adaptation is when the virus attenuates its own virulence in order to maximize its ability to transmit. A virus starts out killing its weak hosts and every time it does so it ends its family tree. The branches of the family tree which survive are the ones that don’t kill their host. At first there is more deaths because the weaker hosts die off. Natural selection occurs leaving only stronger hosts with stronger immune systems. Stronger hosts will kill off stronger strains of the virus. Repeat the process over years and years will result in progressively weaker strains over time. These are adaptations not mutations.
If a virus mutates, it might spontaneously gain some previously unseen spike protein or maybe some enzyme or something that makes it behave differently but this occurs in a single virus cell which isn’t actually a cell it’s called a virion. It has to survive the immune system of its host long enough to multiply and spread. If it doesn’t it won’t matter how virulent or contagious it is, its family tree will come to an end before it even gets started.
Speculating about the possibility of a virus mutating and causing another pandemic is really not useful because it won’t happen. You can toss around terms like antibody dependent enhancement or cytokine storm which you probably don’t understand or comprehend in the first place. It won’t change the fact that you are being superstitious mor than scientific.