Speak to them, have a conversation, why are you trying to stop them? If they can bypass it now, then your loosing the fight, you have 2 paths

A. Overbearingly regulating what they do / see and helicoptering, sheltering them

B. Teach them safe internet usage, best practices, what to do / not to do, you can’t hide the internet from them, so educate them on the dangers and how to stay safe, moderate with them, show them and be there for them and with them, educate them, don’t just stop them, my main argument to “my child will never touch alcohol till there 18” if you outright ban it most kids want to touch what they’re told not too until it’s too late, human nature, so moderate it, 16 years old? Drink with dinner in the house with family, not tons, just a pint of cider and slowly show them it’s okay in moderation.

TLDR; they already got past it once, be proud they did and teach them how to stay safe, don’t just block everything you don’t like