Doku is one of the emerging stars of the Belgium side, and fresh from a successful first season in the Premier League in which he won the title with City.
"Thanks to City I know more about football. I’m now playing with better players, playing against better teams and that has changed me. I have learned a lot from both good moments and difficult moments," he told a press conference on Monday.
"Pep is very intense, he has a lot of passion. He’s a perfectionist and when you play at City you also become a perfectionist. I had a lot of moments when I thought I did well and then he comes and says to me ‘you could done this or that differently’. I’ve learnt a lot from him.
"But he knows what kind of player I am. He picked me because of my qualities. Not to change me. He trusts me to make the right decisions."
Doku said, however, he had had no contact with his club manager while Germany for EURO 2024.
"He hasn’t sent me any messages but I’m sure he watches the games… or maybe not, because he watches a lot of games. Maybe he’s off playing golf. But he does care about the players."
It is the second European Championship for Doku, who was asked if he has lost the element of surprise from the relative anonymity of three years ago because of his high-profile season in England.
"I was less known at the previous Euro because I was 19 and was really there just came to watch. No one would have predicted that I would play against Italy.
"Now opponents are more prepared for me. But doesn't matter that the opponent knows what I am going to do.
"I was also more stressed then. The fact that I now have more experience is an important factor."
Belgium are in a four-way tie in Group E and play their last game against Ukraine in Stuttgart on Wednesday.
At the tournament in Germany, Doku has been used on the both the right and left flanks in Belgium’s opening two matches.
"I feel best on the left, but if I have to play on the right, that is no problem," he said.
"It is a positive that we created many opportunities in the last matches. Hopefully, we will succeed against Ukraine," he added.