Here it is from horse's mouth.
actually many ppl dont understand... In hardware plate-form 5G is just an incremental update for which with enough investment and off the shelf tech buy existing infra of 4G can be upgraded in quick time, but the real jump from 4G to 5G are software solutions which are much harder to optimise...
JIo has deep pockets of Reliance which gives it plenty of buying power to quickly adapt hardware inputs and in house software R&D which is second to none...
From what it seems once in India 5G spectrum is allocated JIO will shortly become one of the biggest 5G provider if not the Biggest provider of 5G services ...