Just a hypothesis based on research that has shown around 100b of covid relief money went into the stock market. Like I said originally, maybe correlation != causation. So there is a link to more money printed by the fed inflating asset prices. If that printing stops due to debt to gdp being too high then that could cause asset prices to stagnate.
https://hbswk.hbs.edu/item/did-pandemic-stimulus-funds-spur-....