I noticed that when I'm editing an animation, unity oftens loads way too frequently and for long periods of time, like 5 minutes for erasing or copying and pasting some keyframes, which is not a lot but adds up at the end.

That happened with the first character I added, and i wonder if it's gonna be the same with the rest of the cast or even get worse and worse the more characters i add.

Basically my question is, from a productivity standpoint, would it be better to edit and add the entire cast as an fbx to another project, then editing all that needs to be edited and THEN export a package and import it to the UFE project or should i just keep working on the same project?

Of course, I'm not talking of creating their hitboxes or even character specific files, only their fbx and their animations.