Comment by iberator

On Android you have stock Digital Wellbeing app.

You can limit many things such us:

Number of notifications per day, Notifications on given hours, nighttime, work time etc, Notifications by application(!), Number of minutes/hours allowed per application before it goes into blocked state till the next day, break or end of work, Priority of notifications, Daily summary of notifications etc etc.

It helped me to cut down mobile screen time from like to 40m.

PS2 : Install Brave browser - it blocks all ads, popups and cookie questions forever. AND it let's you play youtube in the background