I recently heard about the holochain (currently at the end of development) that will start to make possible to build your own local SELF-hosted, decentralized and encrypted chat room (also cloud...)
everything (redundancy mngt, encryption, storage split between servers, storage itself...) will be made by terminal of members of the chat room and no other server will be involved... (Thus it will request storage allocation from each member)
not only the data are decentralized, but then also the infrastructure with the control of it
That could be the next security & privacy revolution...
Exemple :
https://volla.online/en/volla-cloud/