I think there are a lot of people who have questions about how the touch panels on the Steam deckSome might think they don't have much history, but that's not the case. On the Steam forums and Reddit, people are wondering why they don't vibrate the same, and the answer is that each one serves a different purpose: the right one moves the pointer, and the left one acts as a scroll wheel. But the latter is usually not very precise.
At least in my case, the left panel on the Steam Deck has always been so bad that I've ignored it. When I've been using Firefox, Kodi, or whatever program has been offering me a vertical displacementI've always ended up hovering over the scroll bar, pressing R2 (clicking), and scrolling with the left touchpad. Until recently, I saw a YouTube video with a trick that actually worked for me.
Make circles to scroll up and down on the Steam Deck
I don't know how many people feel the same way as me, but I don't feel any precision when I move my finger up and down on the left touchpad. It seems like it wants to move, but in the same direction it can move both where we expect and in the opposite direction, which is confusing.
The trick is quite simple: make circles without lifting your finger. To scroll down (to raise the content), roll to the right, and to scroll up (to lower the content), roll to the left. This way, you'll have complete control.
And what should the circles be like? The Steam Deck's left touchpad is a bit "special," and not all circles work the same. It's best to get used to it, but it doesn't work as well if the circles are very large—they get close to the edges—or so small that you can't tell it's a circle. Medium-sized circles will do the trick.