Rate flowers dont work on a quetz. To solo tame a quetz you need to be on a passenger seat on a tape and whistle attack target and it'll fly at the quetz
Get on the front seat of a tapejare and whistle it to attack the quetz. The speed is just enough to keep up while you pump the quetz full of darts (or lead if clearing for higher levels)
If you're on ragnarok lots of times the quetzels will fly straight into the cliffsides in the highland snow biome and get stuck. I've caught 4 of them that way, just snap 2 regular sized dino gates over them and they get stuck and you can tranq them from the ground
My husband and I when we first did a quetz before the new update used one of our tapajeras and followed it and shot it with darts til it fell then tamed it that way