Will I need a JR Pass for my trip?

In May of this year, I will be traveling to Japan with four others. We plan to use trains to get around, but I am uncertain whether the JR Pass is the best choice for us.

We are planning to use public transportation for the following routes:

• Narita Airport -> Tokyo
• Tokyo -> Mt. Fuji/Lake Kawaguchiko
• Fuji/Lake Kawaguchiko -> Otsuki
• Otsuki -> Matsumoto
• Matsumoto -> Takayama
• Takayama -> Kyoto
• Kyoto -> Hiroshima
• Hiroshima -> Osaka
• Osaka -> Kansai Airport

I would like to know if, in our case, it would be cheaper to purchase a 21-day JR Pass or to buy individual tickets for each trip. We would primarily use the JR Pass for the routes between Tokyo and Osaka, which makes me wonder if a 14-day pass would suffice.

Additionally, I want to minimize the time spent booking train tickets while in Japan, so if the JR Pass is slightly more expensive than booking individual tickets, I wouldn’t mind paying the extra cost.

Thank you very much for your help and advice!