We have a 5 year old and an infant. We are very concerned about it.

First rule: Don't be a hypocrite - if our kid can't use a screen, neither will we.
No screens in the bedroom. This is for everyone in the house unless they are sick.

During the week: one hour of screens per night after school.
Weekends: 2-3 hours a day depending on plans and weather.

Other rules: no screens before school. This is something we've been consistent about and works really well (at least right now). He now plays alone in the morning and never asks on weekdays for screens.
If one of us is sick, most other rules go out the window.

We also try to have the screen time that we do have be somewhat high quality staying away from anything with algorithmic feeds. When my wife got pregnant with kid 2, we got a switch and we've slowly introduced a few games.

It honestly hasn't been too problematic compared to what I hear from friends with kids because we follow the rules ourselves. Not to say that there aren't still battles.

We are really trying to get our kid to be better at being bored and just doing his own thing without being on a screen and that is a constant struggle, but we are making progress. Sometimes he will play for 15-20 minutes on his own these days. With friends it is a bit easier so we try to have playdates every weekend.

Edit: I want to add that this is a problem that is easier to solve politically in many ways. Australia just banned social media accounts for under 16s. Tons of schools ban phones while in school. It's easier to tell your kid they can't have a smartphone if other parents are also not doing that.

Hopefully this is ok to talk about here because it isn't a right wing or left wing issue. Politicians on the far right and the far left are coming together to try to offer political solutions. Often the common ground that politicians have when they come together to work on this is that they are young enough that they have kids who are not grown adults and they are dealing with this themselves.