There’s a mountain of differences between the Pearl Harbor battleships and this submarine. For starters just the fact that this is a submarine is a huge difference. The key component of a sub is the pressure hull. I believe US subs cast the pressure hulls as a single massive piece, so no seams that could suffer from poor welding etc. I know older Soviet subs were two pieces welded together, but I’m not sure if newer ones are one or two pieces. Whatever the case, if that explosion did significant damage to the pressure hull then it’s basically a complete write off. They might be able to salvage components from this sub, but they would have to cast a whole new pressure hull, which basically means a whole new sub.

Then there’s the more modern electronics in these subs. The kilo class subs were first launched in the 1970s, so 30+ years after Pearl Harbor. There’s bound to be a lot of computerized and other electrical gear in the sub that doesn’t take too kindly to being submerged in salt water for a prolonged period of time. There’s bound to be a lot of different metals used throughout the sub, and not just in the electronics. Put different metals in a salt bath and you get electrolysis, which corrodes the metals over time. I doubt raising that sub to the surface and drying it out will be a quick process, so there’s a lot of time for equipment to corrode beyond usefulness.

This sub was equipped to launch missiles. It is unlikely Ukraine would say why this one.

Could be the only had the ability get one (that is only one sub sea baby), and it was random chance. Could be they could bypass the protections on this while the others were protected by something (sea nets, sonar...) they didn't think they could get by. Those are two obvious ones I can think of (and thus assume Russia knows more than me if either is possibly true). There may be a completely different reason I can't think of though - again I would expect Ukraine not to say (of if they say it might be an incorrect misdirection)