travelling on the 12th of august till 19th august 2025

hi
need to know as we wont be using the pass everyday as i read up on the rail pass it stated that it really isnt necessary.
is this a fact. as im confussed now., we want to travel around tokyo and have plains to go to hiroshima with the bullet train.
im not sure about all this. so i need advise to what to really do. and is the suica card better as it also is a form of public transport including trains , subways and buses.
as we are only there for a week really need to know if this is worth the expense for our needs.
and also to travel to all the major cities just for the day what would your advice be.
as also we want to see the jr yamanote line and just get off on each stop that we have looked up in tokyo and can this pass be used to jump on and off and back on as many times as you like during that day of travel eg the 13th of august?
and on going to hiroshima can you just purchase a ticket for that day of travel or is this the best option to purchase the jr pass ?
really need a huge amount of advice please.
thank you
kind regards
beatriz