I'd be afraid of tearing pads while crunching away with side cutters.
I'd definitely try to lower the solder melting point if it's lead-free by mixing it with another type.
I'd remove with hot air using some underside preheat or without hot air make a rectangular heat spreader in 2.5mm² copper wire then drown all the pins in solder heating with 2 irons, one on each row, if available.
Don't go too hot, don't apply force