I believe you're right that "we are doing work" is an appropriate translation, but there is no other single verb that means "to work" -- you have to say "to do work" in Hindi. So, although you are right that "we are doing work" is a valid translation, I would argue that "we are working" is usually going to be the more natural translation for this.
काम कर रहे basically means working (or, more literally, doing work). काम means work, कर is the verb stem of करना (to do), and रहे indicates that the verb is continuous (like adding the ending ing to a verb in English).
verb stem + रहा/रही/रहे = present continuous tense.
Perhaps the following links will help you to better understand: https://www.learning-hindi.com/post/1004288841/lesson-35-the-present-continuous-tense https://hindilanguage.info/hindi-grammar/verbals/participles/verb-stem-plus-raha/
Hope this helps!