How to save files offline on Mac

I cloud is based on the internet and in my country the internet is slow and often not properly available

I am using SOnoma on a MACSTUDIO m1

What can I do to keep my files in my machine or in external backup drive ONLY?

From the Preferences it seems this is impossible

Yet I have lost several files because of I cloud - I have several machines for various usage and each link to Icloud: I just do not want it.

I understand My mac mail accounts go to the Apple server but why the rest?

I want to be free to use the machines I payed the way I want to.

I do not believe using or not using Icloud is a crime or an attempt to go agains t the security system

Can I do anything or will I continue loosing files, banck infos, important irreplaceable photographs and so on

[Re-Titled by Moderator]