There is a Klingon Zone on the star charts seen last year, with Qo'noS as the capital of this zone.
Going by the charts and the dialogue that we have available from the canon, the Klingons were a rapidly expanding empire from the mid-23rd century to the mid-24th century. However, they could not hold onto many of those claims as they reverted back to who had them before, were occupied by other powers, like the Romulans, or became neutral. By 2399, the empire had shrunk in size with a large area of space becoming neutral space. By 3189, they had reclaimed some territory in the Beta Quadrant. I would say that the Klingons were still around, they had their own government and an interstellar fleet for protecting their territory.
Charts used were seen in "Magic to Make the Sanest Man Go Mad" (DIS), "The War Without, The War Within", (DIS), "Maps and Legends" (PIC), "Die Trying" (DIS), and "There Is A Tide..." (DIS).
I like to think the Klingons were watching the assembly on remote and choose to abstain from voting. There were 60 delegates or so, yet the number of voting delegates (30 for, 20 against) does not match that number making it probable that some did abstain.