Of the 11 young Brits who have tried their luck in the Bundesliga, only Sancho has made the jump from bit-part impact player to first-team regular.
Nagelsmann believes that the Borussia Dortmund star has benefited from being given time to settle.
Sancho was signed from Manchester City in August 2017, yet only played his first 90 minutes in the Bundesliga the following January.
“These loan deals only work if the player is there for perhaps two years, and he has time to acclimatise,” he told SID.
“Jadon also took a bit of time to get going. He had time to develop, but others don’t have that.”
By that logic, Lookman may have a better chance of establishing himself at Leipzig than Welsh international Ampadu.
Lookman spent six months with RB Leipzig in 2018, and has now joined on a permanent deal.
Ampadu and Kenny are on one-year loans and have just a season to make their marks in German football.
For now, Kenny feels he is settling well, though there is one thing he misses already — a certain chain of chicken restaurants.
“If I could bring one thing over from home, it would probably be either my family or Nando’s,” he said.
“I really miss Nando’s.”