14 day JR pass- is it worth it

Hi. I’m travelling to Japan this year with 3 other family members, so 4 adults. Our itinerary will be Tokyo 5 nights ( day trip to Hakone) Kyoto 4 nights, Hiroshima 2 nights (day trip to Miyajima) and Osaka 3 nights (day trip to Nara) then back to Tokyo 1 night.

I’m confused as to wether or not buying the 14 day JR pass would be a big saving or wether we should just buy tickets on the Shinkansen as we go .

Also confused at wether or not the JR pass will get us on trains/buses in all the cities when I’m travelling around during the day within each city or if we have to purchase these tickets as extra tickets.

And am not sure about the convenience, eg, the ferry that is covered by the JR pass to Miyajima does not leave from the memorial peace park at Hiroshima and takes longer so we would not catch it anyway.

Any advice would be greatly appreciated. Thanks