While I don't appreciate the implementation of "security" generally involving monopolization, I think it's important to note that you only need age verification

While I don't appreciate the implementation of "security" generally involving monopolization, I think it's important to note that you only need age verification for things that are irrelevant to children. In fact the entire point is to exclude children. So a non-Google/Apple device is still perfectly usable for them if (or even specifically because) it cannot pass age verification/attestation. Really the main concern should be use of attestation for banking/government stuff.