Can I vent a window air conditioner through a joist space for 30 feet?
I suspect the owner's manual for your AC would spell out the duct length capacity but I strongly suspect that 30' is much too long, especially with that vinyl duct which is, quite frankly, garbage.  Corrugated duct in general is not a great idea for long runs because it creates so much more air resistance but if you have to use it, look for the metal type which looks like a Slinky wrapped in tin foil.  Not to mention it will last much longer. Better still, if you can figure a way to route it, is rigid sheet metal duct which you can get at a big box store and perhaps fasten smaller sections together as you push it ahead in the overhead space, sealing the seams with foil duct tape.  That would give you the best chance at a satisfactory outcome but again, I think you will find 30' is too far for a small unit regardless...

BTW, do not under any circumstances vent into the ceiling space.  Utter disaster in the making ;)