We should absolutely keep a critical eye on pop science, check for bias and straight lies. We should absolutely be aware of the concept of Moral Panics and see our own opinions in light of that, yes.
But does that mean technology addiction is actually confined to the small realm of literal digital gambling?
Since this discussion is already chock-full of metaphors, let me make one as well: I am currently in Italy, where a good dinner is usually accompanied by a good wine. Say I am an alcoholic - would this kind of drinking I just described be the core of my addiction? No. Would it, in itself, be even negative? No. Would it be a good idea for me, the alcoholic, to refrain from all drinking, including this? Absolutely fucking yes.
Just because technology can't be called "universally bad", just because this kind of addiction is new and hard to measure (no pendant to measuring tobacco residue in the lung etc.), does not mean it does not exist.
If I may paraphrase the Wikipedia definition here, addiction is strong behavioral urge despite negative consequences.
So, maybe smartphones do not alter the literal (biological) attention span. But what about your ability to do deep, concentrated work? Mine definitely got fucked, and I can point at root causes.
So, maybe we haven't established causality between screentime and depression. But I will tell you what you can't do when your first and last interaction of the day is checking notifications: Quiet and serene self-reflection, or any other kind of self-therapy approach.
Maybe my anecdata is an outlier, but I can certainly correlate less screentime with happiness, monetary success, romantic satisfaction, sleep quality and psychological health quite clearly, down do an amount of screentime way below what's considered average.
/rant
This was longer than expected, maybe my point is just: Absence of proof is not proof of absence.