When using OneDrive, you have a local copy and a remote copy in the cloud. If you have no Internet connection, you should still have access to your files. Then, when you regain Internet access, your files should sync to the cloud. Using your File Explorer, you should find your files in the OneDrive folder.

To stop using OneDrive, create a new folder where you want to store your data. In File Explorer, drag and drop your files from OneDrive. From here on out, make sure to "Save" or "Save As..." all your files to this new location. You may catch some static from Microsoft OneDrive from time to time. I just smile when this happens.

BTW, there are cloud storage products that won't try to hijack your computer. I use Dropbox, but there are others.