Sight Reading With Both Hands
Reading one hand is one task. Reading both is not two tasks at once: it is learning to see the two staves as one picture. The passage below is level 5, the first level where every passage is both hands, with off-beat entries, more accidentals and the first syncopation.
Play it on the keyboard under the staff or on a digital piano over MIDI. Right notes move you on; a wrong one is marked and the reader waits.