POJ has been arguably the Pens best d-man this year, he's not going anywhere unless it's for a massive return.

I disagree, he’s physically weak and needs to go

You're wrong. That's all.

More minutes he gets, worse pens play…. But this wasn’t about him, just what 2024 could look like

This is an ignorant statement. Right now Joseph is getting a lot of ice time because Letang and Petry are out. Those two lead the team in ice time, and that puts a heavy burden on the rest of the D.
Joseph also still doesn't have much NHL experience, but he's proved himself in my eyes. Our defense is not better without him unless we aquire a better defenseman.
The Pens issues have come from our top 6 cooling down, important injuries, and the fact that we're old and slow. Joseph is not the cause of any of that.

Sorry but I disagree…. You can just see the other team push him around and dominate when he is out there. The only thing that would make him near replacement level would be Ahnold level steroids. He’s embarrassing to watch

I can see his talent. I've watched nearly every game this season and the number of times he stands in a bad way are far outweighed by the good. And I'll remind you that this is a young man with little NHL experience, and you're considering him valueless because he's not having an impact that's far higher than what anyone really expected of him.
And I don't know how you can throw out a blanket "I disagree" and not even say anything about the other issues that this team has. Trading POJ doesn't fix our problems. This trade will not move the needle now and it will not later.
You said you want to see what 2024 will look like? It will look like POJ in black and gold where he belongs.