Asus promised to bring the unlock tool back soon after they took it off in last august.
They have yet to re release it but my guess is that they are waiting for the release of the Zenfone 11 line, since normally that's the one that gets the most benefit from unlocking bootloader.
Every representative I've spoken to, including forum moderators have told me they don't know so it will be up to the developing team. The bad news is we can't contact them directly.
