Question on Logseq Sync and device storage

I am currently using iCloud to sync my iphone and Mac Logseq graphs. But, I am considering Logseq Sync and have a question:

If I use Logseq sync, does it store all my files on each device? I assume it does, but just want to check. I am not sure if I want to use up a big chuck of iphone storage for the files. I know icloud also store files on each device, but with icloud it will remove or minimize lesser used files.

I’ve heard others have has issues with icloud, but I have not yet. But I do see the benefits of not being on Apple or anyone’s cloud.