We actually considered that! (But not with a jigsaw, but by running a circular saw adjusted to 1.5" depth along the lines so we could avoid unscrewing the whole thing, but after a few attempts it was clear that was going to take even longer than doing it the right way).
We ended up removing and respacing the two spots where the pooling was the worst, (thankfully near the two ends) but on the rest of the deck (and this is really embarrassing and not at all the correct way to deal with it!) I just got out the fattest drill bit I had and went down the line drilling a drainage hole between the studs every 2' or so making sure I didn't hit a joist underneath and then I flushed out the wood shavings so they wouldn't make the problem worse when they swelled up and I covered it with an indoor/outdoor rug lol.
Like I said, we weren't pros either, but anyone can definitely learn from our mistakes :)
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