I do not understand as I see many threads here with soft spots being repaired.
You say soft spots are not worth repairing. Or only when they are the entire length of hull?
One of my hulls has maybe 2/3 length. Front worse and middle not to bad.
The port hull only has these soft spots up front only. The lower portions are all fine.
Small soft spots can be repaired by injection if they're caught early. "Large" areas of soft spots are generally not worth repairing. 2/3rds of the hull is beyond a large area. Large areas in front of the forward pylon are almost always not worth repairing. The problem is that if you have large areas of soft spots, most likely the foam core has deteriorated (so the problem is more than just delamination). The deck should have virtually zero flex when you press down on it with your hand. It should have a very crisp, solid sound when you knock on it with your knuckles or with a coin.
You can try injecting the deck but at the very best, you will end up using a lot of epoxy meaning significant additional weight. Most likely, injection will not fix the problem and you'll be throwing good money after bad.