both your comments are laughable.
Have you looked at the FA market on defensemen?
https://www.sportsnet.ca/nhl/article/top-nhl-ufas-position-looking-10-best-defencemen-available/
every one of them is basically 29-30 years old. All of them want long term contracts, at high value.
You can sit here with your heads in the clouds, but young defensemen capable of filling starting roles go at a premium.
POJ is worth more than the 1st he was drafted at, because he's been given the time to develop. He can play now, not wait.
JJ cost is a 2nd to dump.
The net return on that is going to be roughly a 2nd.
The penguins aren't pressed to trade JJ, they can buy him out. They don't care about the length, the team will be long dead before it will even matter.
Which means you can expect to pay if you want defensive help.