Agreed, I can't see anything stopping it mutating further if the opportunity arises.

I believe the understanding is that the omicron variant may have evolved further in an immuno-compromised person (e.g. with AIDS, or undergoing chemotherapy), since it got to stay in the host longer without being killed by the immune system, it racked up more mutations until it got to its current virulent form and started infecting other people.

And there's absolutely nothing stopping that from happening again I guess.