Is there a need for the JRP or are individual tickets better?

Hey everyone! I'm travelling to Japan next year. Here's what my itinerary so far:
1. Land in Kansai INT, explore Osaka for 3 days and 2 nights (go to Universal studios)
2. Go to Tokyo and explore for 6 days, 5 nights
3. Go Tokyo Disneyland for 3 days and stay at the hotel
4. Travel to Narita Airport to fly back
I have yet to decide which cafes/touristy areas i would want to go yet but the theme parks are my main priority. What do you think? Should i get the JRP with the Nozomi ticket or just buy every ticket individually? Alternatively, should i just take a cab everywhere hahaha. I'm not sure, please help.