I just upgraded from Mojave to Monterey, and have this problem too. I saw so many have the same frustration as me.

I found an answer in a way, at least on my iMac, 2019 27". Playing around with keys, I found if I hold down the fn key in the lower left of the keyboard and clicking using the up and down arrows, it doesn't scroll exactly, but shifts 1 page height of whatever page visually shows on the screen. It moves down or up one page height. So again, I hold down the fn key and click an arrow up or down to move the page. Hope it works for you too.