Actually, all my dragons are unlocatable, but in particular I’m trying to find dinraal. Of note, I’m in the late game after you get all sages, so a specific castle quest has opened up for me. Does that block their spawn? Has anyone encountered this?
They’ll pop up again. Chances are they’re flying in the Depths.
Dinraal is consistently the hardest one for me to find as well. I don’t think the castle quest blocks the dragons.
I think sometimes they just disappear for a bit. Have you checked for them underground yet? They hang around there sometimes.
To add to this, the dotted line on the map OP has shown is the route in the depths.
Also the lesser dragons, their route is supposed to be 30 minutes. Perhaps just stand at top of tower Thyplo for a bit and look towards east