https://www.capfriendly.com/armchair-gm/team/2882494

Center is really an area of strength for NJ.
When healthy, their top-3 centers are Hughes, Mercer, Hischier.
(I think all three should stay at center and playing Hischier at 3C will be fine).
McLeod is 4C. Sharangovich is also natural center who just needs to work on faceoffs.
Kuokkanen and Zacha can also play center and were both full-time centers as recently as two seasons ago.

For 3C: I don't think we need to make some big trade. Maybe if a Bjugstad-like player came cheaply. Or a Jay Beagle face-off specialist type. Or a Tyler Bozak. (Or get Zajac out of retirement for one more run).

They may need another depth d-man on right-side as 7/8 guy until Subban moves on at deadline, then as 3RD for 1.5 years as kids develop.
Luke Hughes will likely arrive around April 2023. Reilly Walsh isn't far away. Case McCarthy could be good defensive option long-term at 3RD.
Also, both Smith and Bahl have experience playing right side.
If we don't re-sign Severson, they will likely need to add a player higher in lineup.

For 3RD: I think Subban is good for now. They guy I liked in off-season was Justin Schultz. Or any veteran with good success in both possession and zone exits. The ideal would be Rasmus Anderson for the style of hockey NJD plays and their needs on back end. But he would cost too much for 3RD role. Matt Roy would also be great.