You could just use a popup that says “Are you over 18 and willing to see NFSW content?” like most NSFW website do, but I guess that doenst generate enough money unlike forcing accounts does.
Since when does a reddit account require me to submit ID proving I am indeed 18+? I literally see no difference in reliability between requiring an account where one claims to be 18+ and a banner where one has to claim to be 18+. In both scenario’s you are relying 100% on user input.
Reddit be like (programming.dev)