This is undoubtedly a major contributing factor.
Prior to Facebook, Snapchat, Instagram, Twitter, Tik Tok, et.al., there were millions of kids nationwide who went to school and got bullied, ostracized, marginalized, or on the other end of the spectrum, spent every minute in an extremely competitive state of mind....competing with friends/classmates for ranking and status in academics, sports, cheerleading, dance, music, art, and on and on.
The difference is, back then, as long as they didn't answer the phone, home was a place where they could--to paraphrase the Cheers theme song--take a break from all their worries. Or at least take a break from some of them, and for at least some amount of time.
Today, they are interconnected 24/7/365 with their friends, support groups, classmates and competitors, and also their tormentors (in whatever form that torment might take).
To make matters even worse, they're also in near-constant connection with their teachers. Doodle's daughter does 90% of her homework on a laptop provided by the school. Almost everything is digital and is turned in and graded via Google Classroom, Canvas Portal, and Infinite Campus. Not only that, but the parents also have instantaneous and constant access to details on every homework assignment, project, quiz, test and final.
So it's not merely a matter of the stereotype of the modern teen being unwilling to disconnect and disengage. In fact, it instead is proving to be a virtual impossibility for them to do so. Thus, there is no way you'll convince Ol' Doodle that this isn't having a dramatically detrimental impact on their mental health, especially as compared to prior generations.