Paying off mortgage or buy another house

I would say hold the cash for now until the vol is over

Where do you live? Best is if you can move and turn the current house into a rental. You then sell two years later and 500k$ of your gains are tax free

Also, think about it: interest rates are going up. So better invest the same money in tax free muni bonds for almost guaranteed better return. Then use the money from the bond to pay the mortgage

Neither. Leetcode