MacBook Pro M1 Max/Ventura 13.4: Can someone help me understand why search doesn't work...?

Have you reindexed Spotlight?

Rebuild the Spotlight index on your Mac - Apple Support

In addition to what Barney said:

if search generally works when you select "This Mac" but comes up empty when you select the folder, as in your example, this is a problem that has affected many users (myself included).

I was able to overcome this, using advice from another thread (including from Barney)

finder search not working - Apple Community

In my case, I just bit the bullet and ran

sudo rm -rm /System/Volumes/Data/.Spotlight-v100

and it worked.

Also, as Barney-15E mentions the Spotlight search, is an effective search method

I didn’t suggest using the Spotlight interface. I suggested reindexing it since it is not returning results in the searches being attempted. Every search in macOS and some other things you wouldn’t expect to be searches use the Spotlight database index.

First of all, while you searching a file or folder, make sure the name is in the correct spelling.

Secondly, you are only selected downloads, if you select "This Mac" then you will get all the files and folders.

Also, as Barney-15E mentions the Spotlight search, is an effective search method.

Finally, Narrow your search results on Mac – Apple Support (AU)

You misspelled "morning"