Probably been suggested before.
Basically create a separate corp hanger / plex vault like environment specifically for blueprints with multiple folders/tabs for the different types of bps (ships, ammo modules etc - prefer customizable tabs). BPs within the “vault” can be used by any facility within, say, the constellation (or whatever)
Access to use the BPs within the vault could be given via simple roles, ideally for each tab, through the citadel access control lists:
View - allows users to see into the vault/tab and use BPs in jobs
Edit - allows users to remove BPs
Admin - modify tabs etc
Removes the need for BPs to clog up corp hangers whilst giving people the freedom to use them without someone having to make massive piles of BPCs.