At some point some company has to know the clients age to block the access, thus RTA is the only solution that potentially does this with the optional assistance of the parent whilst not sharing any data. Anything else will require connections to a 3rd party which is still a non starter even if using using magic math that pinky promises not to be reversible meaning someone can put 2 and 2 together to get the persons identification. People have caught on to the shell games.
If you're 14, and go to a porn site, you'll be told to go away or prove you're 18+, which you can't do because you're not. If you try to submit ID (which you likely don't even have), you'll still be told to go away, so why would you do it?
This is not about collecting children's info. It's about not providing service to them.
Additionally, nothing in these laws (well, from the red states. The new ones out of e.g. California are much worse) says you can't e.g. establish physical verification at adult stores to get an access card or something, giving the same properties we have for other age restricted purchases.
I will instantly delete my accounts if discord or any service implements this kind of tracking.
There are other ways to protect the children.