itinerary help 19 nights

I could use some help with the last 4 days in my itinerary.
I wonder if 2 nights in Hiroshima / Miyami is too much and I should squeeze in Nagasaki. Or do you have a suggestion to stop for a night on the way back to Tokyo. It's not essential that I stay the last night in Tokyo as my flight back home is not until 9.30pm.
This is so far what I have in mind as the places to stay overnight. I've already booked the first 10 nights:
28/03 Tokyo (booked)
29/03 Tokyo (booked)
30/03 Tokyo (booked)
31/03 Nikko (booked)
01/04 Nikko (booked)
02/04 Fuji 5 lakes (booked)
03/04 Fuji 5 lakes (booked)
04/04 Tsumago (booked)
05/04 Takayama (booked)
06/04 Takayama (booked)
07/04 Kyoto
08/04 Kyoto
09/04 Kyoto (daytrip to Nara)
10/04 Kyoto
11/04 Koyasan
12/04 Osaka
13/04 Miyami
14/04 Hiroshima
15/04 Tokyo
16/04 flight back home at 21h30 evening
I appreciate your insight!
Kind regards,
Sarah

I think you meant Miyama rather than Miyami?

I advise you to skip Osaka and go to Nagasaki. I've lived in Osaka for about 2.5 years now (after living in Tokyo for a couple of decades+) and you won't miss much by going direct from Kyoto to Nagasaki to spend at least a day. Check the Japan-guide site for places to visit in Nagasaki. My last visit to Nagasaki was almost two years ago and never get tired of going. No doubt that it will be more interesting than Osaka and the food is much better.

While in Hiroshima make sure you get to a place (not a chain restaurant) that serves Hiroshimayaki. It is truly wonderful. Also check out Kintaikyo and Itsukushima Shrine if you have time. Itsukushima can take a full day if you decide you like it there. Don't forget to eat some of the oysters. Great stuff!

I think you meant Miyama rather than Miyami?

Did you mean Miyajima (which is where Itsukushima shrine is located)?

Sorry, yes, I meant the island Miyajima.
Thanks!