Saving Level takes too long


In my level I have ~1000 custom Actors and each of those Actors has a SplineComponent attached to it.
The actors themselves are nothing special, they currently hold a couple of nested struct properties with some data in it but not that much.

The problem is, that saving this level in the editor takes about 10x longer than loading it, which I find odd.
The size of the level on disk is about 40mb. I ran a “memreport” and found that ~20mb is used by “metadata”, is this normal?

Is there something that can be done to improve the performance of the level saving process inside the editor?