What type of pass or option would suit me better for my itinerary?

This is basically what my trip will look like:

1. Tokyo (Shinjuku, Akihabara, Shibuya and Disney)
   (will be in tokyo for 4 days, Dec 23rd-27th morning)

2. Hiroshima for a two day one night trip. (Dec 27th-28th)

3. Going to Nara, Kyoto & Universal Studios. (Dec 28th-1st)

4. Mt. Fuji for a night most likely. (Dec 1st -3rd)

5. back to tokyo on the day of my flight back home. (Dec 3rd)

I’m not sure if i should get a JR pass or if it’s even gonna be worth it. I will be in Japan for 12 days. I’m a little confused and overwhelmed with all the subway lines i’m just not sure which type of transportation i should use. I was thinking buying the round trip bullet train ticket from hiroshima to tokyo and moving that to the last destination but i feel like it’s gonna be a lot of moving up and down. I am also hesitant on buying the national JR pass considering it is almost 600 for a 14 day pass for one person. If i buy the Kansai-Hiroshima pass, will i need a separate pass for me to go to fuji and tokyo for my flight back home ? if so, what’s my best option for that ?

Any suggestions?