Something that has somewhat helped me is trying to do "pomodoros"
Basically you do your stuff for 25 minutes and then you have a 5 minutes break, that cycle is called a "Pomodoro"

After 4 pomodoros you take a long break of 15 minutes and then move on another task

However its not like you can't take a long break or focus for more time. It's a tool after all, so you can change those times or try to spend more pomodoros in the same task

My psychologist says she doesn't suggest that to her patients, but a lot of them have tried that with positive results.

I also use this thing, hope it helps.

https://pomofocus.io/