First, this is deeply deeply misleading, to the point of being misinformation. The idea that a version of COVID will pop out that renders the current vaccines completely useless is founded in nothing but alarmist speculation. Could it happen? Maybe. But we have a virus now that's known to be dangerous, for which we have a vaccine that's very effective. To not take that vaccine, now, based on this speculative fear is completely nonsensical.
Second, it's a false dichotomy:
c. Take the vaccine, get a mild breakthrough case of covid later that builds even stronger protection.