Working with big MBOM structure

Hello, all!
I try to create MBOM structure for big Assembly (about 2500 parts and assemblies).
I came across the fact that it takes 3 minutes to create an manufacturing assembly and 2 minuts to create Scope between EngItem and MfgItem. It is completely unproductive.
Do we have any maybe metodology or workaround how to work with big assemblies?