Terraform State Split Migration

Inherited an existing repo in the following structure;

/LandingZone
/App1
/App2
/Modules

Deployments are module based running through CI/CD. Values stored in CI/CD.

Pipeline 3 = Landing Zone + App1, which meant any region or change was affecting the landing zone and app1. This was a problem since our teams were interdependent on changes and resulted in deploying unnecessary resources.

Pipeline 2 = App2 was created after and has it’s own pipeline so that changes do not affect App1 or Landing Zone. There are a few modules needed to call networking and logging, overall the majority is good to go.

Goal is to move App1 or the Landing Zone to it’s own pipeline along with new state.

Is there an alternative (Tool, script) to import or move the state for App1 to a new state file in pipeline 1? I am wanting to avoid picking out 100’s of objects at this point on either side of the migration as all are in production.

My plan was;
Import App1 into new pipeline 1, validate App1 is good
Remove state from pipeline 3 state file for objects that are moved, validate LandingZone is good

Why not move? Potential impact to deployments and uncertainty with this migration procedure.

Appreciate your help!