Kean Jr. should wait for New Jersey redistricting. There could end up being a more Republican district that he would be favored to win in a Biden midterm. Even in the current NJ-07, Kean Jr. probably would have won in a more Republican-friendly year.
NJ Dems have no reason to draw another R-leaning district. Their best bet is to vote sink Van-Drew along with NJ-4 while drawing the remaining seats as safe/likely D.
I think the common thought is that the Democrats will sacrifice Malinowski to make Sherill's and Gottheimer's districts more Democratic. Mainly give Sherill the Union County portions of NJ-07 and Gottheimer take some of the northern towns in NJ-11.
I don't know if they'll do it, but I guess there's something to be said for having a nice, safe 9-3 map.