Unable to open 5.2 project_ construction script crashing engine before loading level

Hi, have been building a virutal music venue, which is my first project and it is pretty intensive, I added the city crowd pack from marketplace which crashed the project. I deleted that folder from the content folder in explorer, but now project wont load, gets to "building construction script (###) then crashes.
I have copied the project , but now that project while opening will crash occasionally, and all Quixel bridge assets cant find their materials, the DMX lighting system I installed is missing, and the decks we built are not working correctly.

I also tried changing the name of the maps, and the project, opened that, and tried to migrate the content folder, but that crashed halfway through the migration.

I have only been using UE for 6 months so please keep in mind.

I have a back-up from before this all started but have put in a large amount of work since then, been saving new levels as I go.
Appreciate any help with this.
Thanks!
Peter