I have installed, and taped, new drywall in some rooms. I intend to hand texture after I finish the floors. I have read, and been told, it would be better to apply primer/sealer prior to texturing and then again after texturing prior to painting. Is this a better approach than texturing before applying the primer/sealer?

Hello everyone, This is a 3 storied brick building with 2 units on each floor. I am on the first floor. I hired a contractor to remove about 7 feet of a load bearing wall after a structural engineers approval. The engineer's instructions were to support it with 3 LVL's 11 7/8" - 15' long with 4 LSLS studs on each end and W/EPC66 Cap and block solid under posts. The work was done per specs laid out. However today i got a call from the neighbor upstairs stating they have a crack about 3 feet long on their floor tiles and a crack about the same size on the wall directly above the wall i had removed. I've been googling regarding this but am finding conflicting information. Some hadnt consulted with a structural engineer and hadnt done things right and then some other places talked about some settling that took place after the work was done. I am a bit nervous as to what might be causing this. Any help would be greatly appreciated (i am scheduling to have the engineer come in and take a look but he is out of town for the weekend and cant reach him until monday). Thank you in advance for your insights here.