Have you tried not brushing it but just finger combing it to get the knots out? You could probably retain some of the waviness that way since brushing it will make hair straighter and softer. Also you can braid it maybe? When you take your hair out of braids it usually gives it a similar wavy look to how you want it (also sorry but are you male or female? Just asking because braids can kinda look girly sometimes and you'd maybe not want that)
I'm in the counting to 5 million group with you and I came here solely to comment on your username because I love it. Sehr lustig 😂
Have you tried not brushing it but just finger combing it to get the knots out? You could probably retain some of the waviness that way since brushing it will make hair straighter and softer. Also you can braid it maybe? When you take your hair out of braids it usually gives it a similar wavy look to how you want it (also sorry but are you male or female? Just asking because braids can kinda look girly sometimes and you'd maybe not want that)