1. Qualcomm X55 modem in iPhone 12 was 1st gen 5G modem. It is known for being power hungry as it is made on 7nm process.
2. Qualcomm X60 in iPhone 13 series was 2nd gen 5G modem built on 5nm TSMC process. It's more power efficient compared to X55.
3. Qualcomm X65 in iPhone 14 series is built on 4nm TSMC process. Naturally it is slightly better than X55 and X60. X65 is the first modem to use AI for getting best data speed in an area of low signal.
4. Qualcomm X70 in iPhone 15 series in 2023 will again be built on 4nm TSMC process but more focused on power efficiency and network signal managed by AI wizardry.
5. Qualcomm X75 and particularly X80 will be real game changer as power efficiency is expected to be better than current 4G modems by usage of 3nm TSMC process. Better 5G carrier aggregation combos have been promised by Qualcomm.
6. By 2025, Apple is expected to have created it's own 5G / 6G modem and because of tight integration between iOS and Apple hardware, we can expect more than a day battery life from those devices.
TBH, I don't think NR CA has been implemented yet. However, X60 modem is the first to support NR CA
Jio has not even deployed n258 band anywhere. Since it would be used for 5G as mentioned on their website, I would love to test it out on my 13 Pro Max US model.