Sync condition

I am currently a Notion user.
I’m using Notion like a personal repository.
A large number of videos, music, PDF files, etc. are stored.

I understood that Obsidian is installed and used locally by default.
I knew that if I want to synchronize with another device, I need to use something like iCloud.

If I synchronize to my phone through iCloud, will all the large files be synchronized together?

Then it looks like the iCloud space will soon fill up.
Does Obsidian only synchronize text-based content by default?

I don’t know the exact concept related to synchronization.