I hate to tell you this, but your question is a bit like the age old, "how long is a piece of string".
I'm in a different place to you, in terms of my metabolic journey, but I'd have quite a lot of cream in my coffee, if I enjoyed it. I just don't really enjoy cream in coffee.
There's a saying that we moderate our carbs to satisfy our blood sugar monitors, and our fats to satisfy the bathroom scales.
One other thing to consider is the coffee, if it is standard coffee may be having animpact on your numbers. Some people find that the caffeine in their coffee elevated the blood glucose. On that basis, if you are enjpy your creamy coffee, it might be useful to try decaf with the same 50ml cream and see the impact over a few days?
No point giving anything you just yet, that you might find a workaround for?