I think the only way out is cold turkey. The number of conversations my wife starts with telling me about some distant acquaintances recent vacation (as seen thru IG) is distressing.
My "social" internet use is more hobby based - forum/reddit hobby focussed content.
The nice thing to do when somebody is behaving poorly, is to ignore it until it becomes untenable (firing them, leaving them, and so on). The kind thing is to address it and let them change their ways.
Wanting to be nice is baked into our social structures - nobody wants to be seen as the un-nice person - but being kind is where relationships and interactions get strong. You just need to do it with empathy.
And even she does some doom-scrolling though news sites. She claims to know it's mostly nonsense, and then says she has to do it to know what's going on. I try not to point out the contradiction too much, because she does limit it pretty well.
If there is no external stimuli to push a desire to change it is unlikely a person will even want to change in the first place.
Hence the other comments, well done you just solved all drug dependency, just stop doing drugs.
Therapy isn't just about how to take responsibility and making changes. It's about learning how to build a support network and the mental resolve to actually go through with the change in the long term.
Blaming the person in addiction doesn't help much without actually taking steps to improve. But it's all too common to believe you have brought an issue to an addicts attention but it didn't quite sink in to them.
Sometimes a phrase like "this is a problem and if you don't seek help I am going to have to take action by doing x" can be a decent wake up call. But if it comes over as aggressive or happens during a fight of some sort you will still not get the response you were looking for.
Inter personal relationships are hard, sometimes it is beneficial for the person's effected be someone else addiction to seek therapy at the same time or even before the addict seeks therapy.
In this case it's even more true, a long term relationship with children is the one place you really do want all the support you can get to ensure the person that needs help gets it and the family as a whole doesn't suffer more than needed.
In this study, they paid people $25 to not use it for a week. I wonder if your wife would agree to that. It seems like for most people who are addicted, you need to go "sober" and not use it all.
That is - you don't need to read 18 different articles about how Pete the drunk defense secretary (and probable assaulter/abuser) likes to text on his personal phone about war plans (including to non-govt officials), but when you see the article pop up in enough of the less biased news places you browse, you get the idea that it's true & bad.
Generally I find business news like FT/Bloomberg/CNBC and (if you ignore the opinion section) WSJ are best for the less-biased news sourcing.
I also browse a bit of known-biased news on each side to understand what each side is going to talk about (and makes it clearer what each side may be BSing about). This is helpful so I don't get jumped by some of my more left/right wing nut social circle when discussing a topic with a known-false partisan argument (as 99% of people just repeat what they see in their-sides news).
No phones in the bedroom. No phones at meals. No phones at the park. (Something like that)
Or even a "let's go out for dinner without our phones!"
I also made a little "Phone jail." It is essentially a shoebox on top of the fridge. I announce when I am putting my phone in "jail" as a way to show my kids that I am trying to have a healthy relationship with screens.
My wife and I have both reduced our screen time (though ew aren't perfect.)