Is there a serious expectation that millions will be attempting to relocate permanently just from this one event? Adapting to a new normal where extreme floodin

Is there a serious expectation that millions will be attempting to relocate permanently just from this one event? Adapting to a new normal where extreme flooding happens far more regularly seems intuitively slightly less problematic than trying to adapt to frequent extreme heat/drought, storms, fires, outbreaks of disease etc. - indeed the ancient Egyptian empire is often presented as having thrived partly because of regular flood events, and there are entire cities in countries like Bangladesh that routinely cope with flood events that would be considered extreme in most other parts of the world. Having said that Bangladesh itself has been seeing huge levels of internal migration (primarily to Dhaka) triggered by recent flooding, so clearly there's some point at which continued adaptation in a given area becomes impossible, at least not without massive investments in infrastructure that are beyond what many such countries will be able to afford. Still, if forced to choose between a neighborhood that suffers frequent mega-floods and one that has to deal with regular droughts or super-cyclones or uncontrollable bushfires or indeed a permanent increase in water levels due to sea level rise, the former seems the least worst option. Interestingly two of the most deadly natural disasters in history were flooding events along the Yangtze River in the late 1800s and then the 1930s, killing millions. Yet people still live there in huge numbers today...