I use a log and a bit of small stuff to get the fire going, then it draws wonderfully. Over the evening, you can add 2-3 more logs and have a pleasant warmth.
Hmm - maybe one should ask an expert about that. But somehow I don't think that with a 5 kW stove and 1.5 logs you can achieve the necessary heat to burn cleanly... But maybe it's because all the fireplaces I know are rather in old buildings and accordingly not up to date.
I can only speak for myself, the stove fitter commissioned the fireplace with us and explained how we should heat, the temperature in the fireplace is also within the technical specifications, so it should be fine.