I am using macOS Big Sur, and notice if I use Finder and navigate to a folder, and search for a file by name, then it shows me results, but is for the whole Mac. This is really confusing. I will have to remember to click it from "This Mac" back to "FolderName" How do I make it search within that folder and its sub-folders by default?
When you search from Finder you get a window like the following after your search. For example I went to the folder "On My Mac" and did a search. The results are shown in the image below.
Notice near the top of the image is the word search. Next to that are the phrases This Mac and "On My Mac". This Mac is selected and this displays my result for my Mac. If I click on "On My Mac" then the results for that folder will be displayed.