SPY Correction, How far?

So the SPY, NASDAQ, DJI have all ripped along with the markets in general for some time now. Regardless of pullbacks, the long-term view on simple economic growth combined with the ongoing continuous public health crisis results in what could be some of the most overextended markets ever. While at the same time the markets are incredibly stable in a long-term sense, my opinion is that we will retrace all the way to 200 MA around 400, possibly lower. Given the terrible situation our government has put us in it's hard to judge in such an artificial market nowadays. If this bottoms and bull trend continues we see ATH but I don't believe that to be likely.