If you get into the technical definition of IF, then yes, having that creamer in your coffee breaks your fast.
However, I believe that IF is about creating a long-term, sustainable, healthy lifestyle. If having 40kcal of creamer in your coffee helps you get through your fasting window (and makes life more enjoyable) go ahead and add it! You are doing great and at the end of the day 40kcal will not make or break your progress.
It is a marathon, not a sprint. This is not a strict fad diet that you’ll “follow for six weeks and lose 60 pounds!”. Do it however it works for you and don’t worry about labels (whether or not you’re “dirty IF” or “clean IF”). Keep up the great work, I’m proud of you!
I’m new, but learning a lot every day! I think for some people this could def trigger an insulin response which could hinder your weight loss… I struggled with black coffee too but now approaching the end of week two i’m starting to like it, and have my mid day coffee with cream and keto hot chocolate powder and it’s like a heavenly treat I look forward to. Could you try that?