Ah, thanks! I forgot VMware's converter also does V2V. My brain was stuck on it being only used for P2V.
So the converter will convert the vmdk file to a live running ESXi server ...
Is it possible to convert the vmdk file to an ESXi-compatible vmdk file, without needing a running ESXi server?
I would then manually move the ESXi-compatible vmdk file to the ESXi server myself at a later time.