Himeji and Kobe are different day trips
Himeji and Kobe are both easy from Osaka and Kyoto, but they create different days. Himeji is clear, historic and goal-oriented. Kobe is more about city contrast, food, harbor atmosphere and softer pacing.
Choose Himeji for a clear cultural target
Himeji works when you want a strong castle-focused day and a simple structure. It is best if the castle itself is the point.
Choose Kobe for food and city contrast
Kobe works when you want a lighter urban day, food, harbor atmosphere and a change from temple-heavy planning.
Should you do both?
You can, but most first trips are better with one chosen day trip than two half-days chained together.
When to get personal help
Personal planning is useful if you are choosing between Nara, Himeji, Kobe and Osaka evenings inside a short Kansai stay.