Productivity tip: pretend your scrollbar is broken.
Finite Scrolling is Also Bad
Infinite scroll gets a lot of negative attention because of how well it short-circuits humans' desire for novelty. But finite scrolling can be just as bad.
Scrolling is a problem for people like me who do most of their work on a computer, because the internet is the library full of knowledge we need for doing serious work, but at the same time it is also a bunch of loud parties and all our friends and hobbies vying for our limited attention.
Scrolling means more novelty awaits just beyond the border of my screen. If I've been concentrating for a long time or if I'm working on something a little boring, the internet promises the instant gratification of novelty. Maybe I'll just refresh that news website to see if anything interesting happened since I last checked. Maybe I'll see what's new on social media.
I'm not advocating for increasing productivity for its own sake. Taking breaks is healthy. But I also know how quickly a healthy break can turn into a soul-destroying doomscrolling nightmare.
As a fix, try increasing the cost of scrolling. If you're really crafty maybe you could connect your operating system to a stationary bicycle or treadmill so scrolling is only possible if you're also exercising. Or write a browser extension that allocates a "scroll budget" for you each day, which you can use whenever you want.
A low-tech solution for mouse users is to simply tape over the scroll wheel. You can still navigate pages, but you have to find the scrollbar and carefully click and drag it. It only adds a little extra bit of friction, but it might be enough to change your habits, and over time increase not only your productivity but also your overall wellbeing.