My kids don't see any of that stuff, because (like most on tech sites) I have half a brain when it comes to technology. Every device in our house connects to my own DNS server using DoT or DoQ (OS depending), and the kids' devices are heavily filtered. Adult sites, gambling, drugs, social media, and other such sites are all banned (along with all ads, trackers and so on). Their searches are all enforced with safe search mode, and things like YouTube show in restricted mode and comments are disabled.
All DNS servers but my own are blocked (so apps trying to connect to, say, Google DoH to bypass my network are blocked dead), and all plaintext UDP queries on port 53 redirect to my own DNS server, regardless of where they were headed. My kids think the Internet is all educational and funny videos, and homework sites. This isn't a device issue, an Internet issue or even a legislative issue. It's a parenting issue. I agree about social media though, it's cancer (and designed to be that way).