I'm currently using an app (ironically) called AppBlock which is helping a bit.
I used to work in the office and leave my phone in the car but now I'm wfh I need extra help stopping myself from getting distracted. It's easy to slip from thinking I can just do a bit of admin while waiting for a meeting to start or if I'm on hold to realising I have zoned out for a chunk of time. Now I have blocked apps from 8.30 - 5pm on work days. I'm tempted to pay for the full version and set other 'off' windows, particularly around bedtime / getting out of bed.