To buy or not to buy the JR Pass / any other passes

Hi there.

I will be traveling to Japan in Jan and I am unsure if I should get the JR pass and if there are other passes I should consider getting since there are so many different types, I'm honestly confused. Appreciate if I could get some help based on my itinerary:

2 Jan: Arrive in Tokyo Narita airport
2-7 Jan: staying in tokyo

7 jan: tokyo to osaka
7-11 Jan: staying in osaka and probably taking a day trip to Nara

11 Jan: osaka to kyoto
11-14 Jan: staying in kyoto

14 Jan: Kyoto to Hakone
14-16 Jan: staying in Hakone

16 Jan: Hakone back to tokyo
17 Jan: on this day I'm planning to do a day trip to shirakawago gifu - do you think its doable and advisable?
18 Jan: Depart Japan

Since I am traveling for 16 days, I was unsure of when I should use the pass (be it 7 or 14 days) or if it is even worthwhile at all. Appreciate if u could also let me know if there are other passes I should consider getting.

This is my first time to Japan and I would appreciate any kind of help. THANKS IN ADVANCE!