I think there is at least 80% hope.
But you need the right skills and tools to get it done.
Reading your last query it appears to me that the best route from here is to go on and extract the raw data from each of these NAND chips.
Once extracted you can mount the image in read only mode to examine it further, and possibly decrypt whatever part is left of it.
Your are lucky because sometimes these chips are baked onto the board with the connections on the bottom side leaving them unreachable. In your case the connections are on the sides which makes them accessible with needle or test clip adapters to access the data.
You can see on youtube some repair men have a channel and they will demonstrate to you the process of repair and recovery and much can be learned from there.
It's important however that you have the key to decrypt the data otherwise that obstacle would reduce my expectations from 80 to about 1~5 % and i would consider the funds lost.
Did you say you used Truecrypt ? or Veracrypt ??
If you have the key and the data is there then there is no reason to give up yet.