The Holland attacker penned a new deal to 2030 on Saturday and says Bayern Munich made enquiries over the summer.
Speaking from the Oranje setup this week, Gakpo revealed: "I think it took us a year. Maybe a little longer or shorter, but it's just a long process.
"From what I understand, they (Bayern) have come, but in the end they have bought Luis Diaz.
"It's nice. Of course, I have experienced it differently myself. Such a transfer window can be hectic and stressful for a player and everyone around him. That doesn't bother me anymore.
"It's difficult, because a lot is happening. Other clubs come to you, but you may want to keep your own club.
"Everyone deals with it in their own way, but it is certainly difficult. If the future is uncertain, then it will just be a very difficult story."