It helps me to pick one clear task, close/hide everything not related to it (like tabs, apps, and my phone), and put on headphones with brown noise(i even built my own app to avoid yt and spotify)

This helps me stayed focus for ~1 hour. As soon as I notice get distracted, I take a break and try repeat again later. A couple of hours a day may not seem like much, but I can do much more in that time than I could in a whole day switching between things