How can I stop my macbook from uploading files to the cloud?

Hello!

As part of the sync feature, my macbook basically uploads every file to the cloud - it has 3/4 TB free out of 6TB, so no problems with that

my problem is, sometimes, I need to work on a lot of footage offline, and to do that, I put all of the clips I know I'm going to work in, force-download them to my local mac storage, and then start working.

however, a lot of the times, out of nowhere, my mac just re-uploads them whenever there is a slight hint of internet connected to my macbook, which then leaves them inaccessible when I don't have internet anymore!

I try to disconnect my wifi, but either way, even if i'm not working offline, how can I force my mac to keep all of those files, in my local storage, to make them accessible for me quickly and not have to wait for them to be downloaded?

it honestly feels like i'm fighting with my own laptop, my own icloud and the sync feature thats supposed to help me.

photos for reference:

• I just want to work on that specific folder, i downloaded everything, but out of nowhere it uploads it again