First things first,
This post was written in a university computer, in a Southeast Asian jurisdiction, which may have concerns regarding verification methods when it is used by multiple people.
The UK, Australian, and specific U.S. state-level laws regarding age verification are fearmongering and it will hurt end users even more.
The effect has forced some people to migrate to alternatives to Discord, which each is in beta phase, so not everyone is ready for mass migration.
Another thing is the Fediverse will resist any attempt to implement age verification methods, as it will ruin privacy of each user.
Decentralization reduces the risk of mishandling data.
Also they are laughably easy to bypass. I remember reports that kids were using Death Stranding 2's photo mode to verify that they were, in fact, Norman Reedus