If you only needed the ability to insert a block from another drawing you could add a macro using the
-INSERTCONTENT (Command) or use the ADCNAVIGATE (Command) in a macro to open the drawing with the block in Design Center where you could drag and drop it as easily as finding it on the insert drop-down.
Why add blocks you may not use that add to drawing size when they can be easily inserted with other means when needed? The less places they're stored the easier it will be to update them which would be easiest using Design Center with that ADCNAVIGATE macro.
64bit AutoCAD Map & Civil 3D 2023
Architecture Engineering & Construction Collection
2023
Windows 10 Dell i7-12850HX 2.1 Ghz 12GB NVIDIA RTX A3000 12GB Graphics Adapter