So common that YBOP (long ago) created this FAQ: HELP! I quit porn, but my potency, genital size, and/or libido are decreasing (the Flatline).
https://www.yourbrainonporn.com/porn-induced-sexual-dysfunctions/help-i-quit-porn-but-my-potency-genital-size-and-or-libido-are-decreasing-flatline/