As I said, I use LR primarily for file organization. It recognizes the keywords I had assigned thru Bridge. I don't have a catalog set up. When I need to search by keywords, I just go to the library mode and use the text containing . . . and it works.
Am I missing something?
I assume we are talking about 'Lightroom Classic' here - not 'Lightroom', which is a different animal.
Yes, I think you are missing the fact that LrC
always uses a catalogue, no matter how you use it. Anything and everything you do in LrC is stored in the catalogue file. When you import an image, LrC adds the filename, location and any metadata associated with the file to the catalogue. If you add or change any metadata, such as keywords, colour labels, star ratings, flags or location data to an image, it stores this in the catalogue.
When you install LrC (or possibly when you first run it), it creates a catalogue file in the default location for your system, and continues to use that until the user creates another one, which they may or may not do.
On a Mac, the default catalogue is stored in User/Pictures/Lightroom.
On Windows, I think it's User\My Pictures\Lightroom
If you go to the Catalog Settings in LrC, it will show you the location.
The actual catalogue file will be called 'Lightroom Catalog.lrcat'. If you were to delete that file, LrC would ask you to locate or create a catalog the next time you start it, and you would have to re-import all your images from scratch. Any keywords you added in LrC would be lost.
So 'I don't have a catalog set up' is not true if you are using LrC. You are using it every time you use the program.
You can create new catalogues if you want - as many as you like - and store them wherever you want. Many people just use a single catalogue - often in the default location.