question about stock valuation, p/e ratios in a recessionary market. Trying not to overpay blindly DCA.

We've seen p/e ratios get cut in half or more this year. They say it's because the market expects earnings to go down, right?

So let's say a 40 p/e got cut to 20 p/e in anticipation of 50% decrease in earnings. The stock dropped from $40 to $20.

In this example, when the earnings report comes out, and the company confirms a 50% decrease in earnings, ideally would the stock price likely stay around $20 because it met expectations? (assuming no forward guidance were given)

or should the stock fair value be even lower as a result?