Yesterday, Samsung completed the rollout of One UI 8.5 for all the confirmed smartphones and tablets. Now, the brand seems to be focusing on developing One UI 9.0 for eligible devices.On Samsung's server for over-the-air updates, firmware files for Galaxy A34 and Galaxy A57 featuring One UI 9.0 have been spotted for the first time (via Tarun Vats). They carry firmware versions A346BXXUFGZF1 and A576BXXU3BZF3. Developing…