That would still be expensive, but is it more expensive than blocking the canal?
I can't imagine that being a very quick thing to do.
A smaller less stuck ship or barge you don't care very much about full of explosives.
And you don't need to destroy the whole thing, just shred and distribute the part that's in the canal enough that it's no longer an impediment to navigation. Sure you might be left with 30 big chunks but 30 big chunks can be picked up with conventional marine construction equipment. If the bulbous bow is still buried in the sand then whatever, you don't care.
We're talking about a Mont-Blanc sized explosion here. Definitively messy but with modern engineering I think you could whip up a directed blast that ensures the task is accomplished without unnecessarily digging a hole or some other dumb side effect.
Clearly demolition is one of the things to consider in this scenario, and is at least as realistic as the million-luftballons. It would also make for some fun conversation.
Because then you'd still have to remove everything, but now you don't have one big, controllable system, but you have lots of pieces that will move in unpredictable ways.
The canal is shallow and narrow, and gravity isn't working in your favor here. A ship has a natural tendency to float (even if it currently isn't). Pieces of debris don't. You will have to remove all pieces that break off, one-by-one.