The new storage management tool can be found in the Settings' Storage and Data section. WhatsApp may rollout the update this week along with disappearing messages feature.
The ability to forever mute annoying conversations comes with WhatsApp Beta for Android 18.104.22.168 version and the WhatsApp Beta for iPhone version 22.214.171.124, which also bring a bunch of other changes.
WhatsApp will be getting these new features in beta soon and will eventually arrive for all users in the future.
All it takes is a hacker to get control of one WhatsApp to be able to replicate the same hacking technique on everyone in your WhatsApp contacts and groups.
WhatsApp does not have Dark Mode, Secret Chat or Self-Destruct messages like other instant messaging apps as yet.