Japan itinerary feedback – Tokyo/Kyoto/Osaka vs adding Kinosaki Onsen?

Hi! Would love some feedback on my itinerary (solo trip) — trying to balance seeing a lot vs not overdoing it.

I land at NRT at 2:30 PM on April 9, so realistically I’ll get into Tokyo around ~5 PM and that first day is really just dinner + settling in.

Current plan (Option 1 – no Kinosaki):

• Tokyo: April 9–13 (5 nights, ~4 full days)
• Kyoto: April 14–17 (4 nights)
• Osaka: April 18–20 (3 nights)
• Fly to Seoul: April 21

Alternative (Option 2 – with Kinosaki Onsen):

• Tokyo: April 9–13 (5 nights)
• Kyoto: April 14–16 (3 nights)
• Kinosaki Onsen: April 17 (1 night)
  • Already have a reservation at Nishimuraya Hotel Shogetsutei, but plans are flexible
• Osaka: April 18–20 (3 nights)
• Fly to Seoul: April 21

Alternative (Option 3 – more time in Tokyo):

• Tokyo: April 9–14 (6 nights, ~5 full days)
• Kyoto: April 15–17 (3 nights)
• Osaka: April 18–20 (3 nights)
• Fly to Seoul: April 21

My questions:

Is Kinosaki Onsen worth the detour for just 1 night, given the travel time?

• Or is it better to skip it and either:
  • keep more time in Kyoto / reduce travel days, or
  • add a night to Tokyo (6 nights total, ~5 full days)?
  • do a night in Hakone for a ryokan experience?
• Does this overall pacing feel reasonable, or am I trying to do too much?

Would really appreciate any advice — thank you!! 🙏