Sorry I do not understand this trade at all. Who are you going to buy out and why would Columbus get rid of their number 1 center?

Buy out Dubinsky
And he isn’t their #1, Pierre Luc Dubois is.
Dubinsky had like 18 points each of the last 3 seasons. Was benched a lot by torts. He’s going to cost the jackets 5.85 mil next season. This is to relieve some cap like when the jets traded Steve mason and Joel Armia to the habs

If Columbus is using an internal cap then I think they do this but only if the owner is saying he wants to lower the annual cap

Sorry I misread

I don't see this happening, largely because of a few factors:

1) Anderson has indicated he's open to signing long-term with Columbus. I think something like 5 yrs at $4M each would be fair.
2) Anderson's trade value on his own is at least a 2nd, based on what he'd command on an offer sheet.
3) Dubinsky is LTIR for next year. Jarmo has indicated he's unlikely to ever play again.
4) You've neglected to re-sign Vladislav Gavrikov, which Columbus will absolutely do.
5) Wennberg is likely to be traded or bought out, saving a significant amount of money.

Why Columbus are not buying out Dubs?
He could play 4th line in MTL for one season if you retain 2M

See my post above and #3 for the answer to that. He's done.

If CBJ are willing to sign Andy for that money... he worth more than a 2nd in the book...

Well, a $4M offer sheet would only fetch a 2nd-rounder. At $4.5M, that's a first and a third.

In a trade value he should fetch a OK A-Prospect like Poehling + 2nd

I respect your fandom, but if I'm reading this right, you've identified Poehling as an A-level prospect. Which... nah. He's a solid bottom-6 guy, but that's likely his ceiling. He had a VERY exciting single game with Montreal in 18-19, but he's not the second coming of Bobby Hull.

I still evaluate him like a A-Prospect as he doesn't have a full NHL year done and did great when he played in Laval... He is a big body who can skate well... Maybe a 3C as a ceiling

I agree with a 3C evaluation. But that's not enough to really pique Columbus's interest. He looked fine at Laval, but he wasn't dominant the way you'd want a top-6 prospect to be.