It's probably smart to keep the mortgage for the new house is it not?
I am ready to spend some money on renovating the house, but mostly I'd need to find a place to land the extra cash (minus taxes). I currently have nothing in the stock market and that is an option but I'm reluctant to get into stocks at this time of market cycle. I know it's impossible to time the market but it's just so volatile right now and seems highly overvalued.
Generally I've done well with less liquid investments (as I'm impulsive and easily go in and out of stocks, which I need to stop doing so much), I particularly like houses and apartments

So another option is to get another apartment to flip, as I enjoy planning and executing renovations (with professional help when needed of course).
But I'd rather do the flipping without a mortgage so I'd look for studio apartments in my new future hometown where it's way cheaper than here.
There is some added stress to that though - but if the housing market turns studio apartment are always pretty easy to rent out.
Is there any downside to keeping the cheap mortgage that I'm missing?