I had to reload quicken on new computer because loss of old computer (Mac) Cannot restore from online files
By online files, do you mean a cloud backup of your Quicken data? Are you saying that you do not use / do not have a Time Machine backup of your old computer?
You are correct that you cannot re-create a Quicken desktop data file from the data which was stored n your online ("Quicken Cloud") account. You would need some backup of your actual Quicken desktop data file to install on the new Mac. Do you have any backup of files from your old computer?