MacOS Desktop App - Extremely slow decryption - wrong settings?

I am using Cryptomator on Mac/iPad/iPhone, with one 2GB vault and iCloud as a provider.
While access to files on iOS works very smoothly, accessing any file on my Mac freezes the computer for minutes, which is certainly not a normal outcome
Could it be that I am downloading all the files from the cloud instead of accessing them individually (e.g. for edition)? Did I miss a setting?

Thanks in advance

I have tried with a much smaller vault and another cloud (dropbox instead of iCloud) and it remains very slow (still freezes the computer while the doc is accessed/(decrypted I imagine).
Am I wrong with my settings? What should be the mounting location?