My S9 battery usage time remaing is based on my usage over the last seven days.
I factory data reset a few weeks ago and the first time battery usage learning process took about five days.
I see in the image you provided that learning the battery usage pattern is 43% complete. As long as long as the percentage available keeps getting higher everything is running the way it is supposed to. I would give it a few more days and keep an eye on the percentage available.