I think you do have a conceptual problem. IF and EXIST are two different things. IF is a conditional clause whereas EXIST check for the existance of the specified file. EXIST does not search a directory, however, if the provided filename contains placeholders, it check whether there is any file that matches the provided filename.
If you want to search directories for specific files, then you will need to use some kind of recursive dIR() function, for example the DIRPLUS() UDF that was recommended to you.
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There are two types of vessels, submarines and targets.
