In no particular order, but most have a cause and effect.
Cp3 on the decline - Don’t draft Halliburton
Trade for a player who plays in the same position as the face of your franchise - and don’t remove his NTC so when it doesn’t work you are stuck with him.
Don’t address the need for a strong defensive big - Have KD playing the 4 & 5 and not the 3 & small 4 (in stature) that he really is.
Have 4 2 guards and no pg for a season and think somehow you’ll work it out.
Trade away future - Camara and many picks that hasn’t worked out.
Draft Ayton - Doncic as a 3 next to Books 2 and cp3 as the one for a season or two

Leave Jones making trades and not focusing on building a competitive team.
I could go on but many have already covered it.
I’d change Jones myself as he’s consistently not helped build a structured or competitive team.
Trade KD and try and get some future back.
Start with what Book needs around him and go from there.