Mass Upload of files

I was wondering if it is possible to use Katalon to upload many different files in a folder in a format such that it uploads all files inside the folder, besides other folders.

For example, it uploads “artifacts”, “eclipsec”, “katalon” and “katalon”, but not the folders.

Katalon supports the Java and Groovy programming languages. So, yes it could. However, you would have to program it to do so. There are likely some examples on other Java/Groovy related sites that can give a good beginning.
Edit: if you are wanting to just do the file transfer, then MS Excel has programming language, Visual Basic for Application, that you can use to create a file transfer program. Again, you would have to build the program yourself, but there are LOTS of sites on VBA programming.