It does look like 622XY
But if the X is zero -- i.e.: 6220Y -- then that would correspond with 9th brigade (62x0x).
Assuming this is from 9th brigade, well it would as good as confirm that 9th brigade has at least 20 J-20s...
Alternatively (and somewhat less likely imo), is that this is not 9th brigade but some other brigade -- however the placement of the third digit in 62
2XY, means whichever unit it is from, it has at least 20 aircraft.
Now, I think it's unlikely that there's just a new unit randomly popped up with an additional 20 J-20s.
But the idea that 9th brigade has at least 20 J-20s to me sounds very reasonable indeed.
@Deino