In my experience with working with stepped and stepless shafts for all types of players and based on my own personal experience, there is no difference in feel for stepped vs stepless shafts. There are differences in the profiles of the FST 115 stepped and stepless that might relate to a feel difference. The Stepped is stiffer in the butt section and the stepless is stiffer in the tip section. Not by much, but there is a difference. A player might be able to tell the difference. However, the difference is not because one is stepless and one is not. Both are on the softer ends of the flex range. The Score will be a little firmer than the FST, and is closer to the average for whatever flex range you trim it.
FST has decided to not produce the FST shafts in 2023, following what they did in 2022. Big mistake in my opinion and I have expressed that to them, but they are focusing on the KBS brand. It was a capacity issue in late 2021 and 2022. Not a capacity issue now. They just decided to not produce them at his time.