I seem to have a very different experience from most of the comments so far, so thought I should share. My kids are 6 and 2 and we have no screen time limits but also no problems right now. However, I also think nature is very strong, and we're probably lucky that the kids are naturally very active and don't want to sit at a screen for long periods of time.
The oldest used to want devices so bad I was really worried about how we were going to handle screen time, but then COVID-19 happened and he had to basically get his own iPad for school, plus all sorts of exceptional situations in a pandemic, so he effectively unlocked unlimited screen time early.
The most exciting thing to him was being able to message us, and for a while he didn't want to talk directly but only text us. And he searched for all sorts of things on Google, but mostly just educational stuff (strongest metals, tallest person, etc). But he quickly got used to the iPad just being there, and forgot to be obsessed with it.
To this day, the iPad just sits around and he can grab it anytime to look up stuff. He uses it to show us stuff they talked about in school, look up questions he has, listen to music, etc. Basically using it like a responsible adult would. Occasionally he asks to get a game he's heard about, but we just say no and he seems fine with it.
He is not a particularly well-behaved kid otherwise, so I'm don't want to give the impression I'm humble-bragging about him. I just wanted to share that not everyone needs strict limits to develop a healthy relationship with technology. If the pandemic hadn't blown the doors open, we might still be struggling with limits on an assumed obsession, but we stumbled into the much easier solution of no limits and it worked for us.