I need to upload 8Tb data to Swarm. I read docs but I can't understand: does public swarm work?
Swarm is currently still in development and considered Alpha software. There is no stable network, and no storage insurance currently implemented, so there is no way to guarantee that your data will persist.
Furthermore, the current state of the implemented would most likely not be able to handle syncing of an upload of 8TB.
You can follow the development roadmap here: https://github.com/orgs/ethersphere/projects/5