Jesus did indeed contradict YHWH. The two couldn't be more different.
The OT god was very legalistic. For example killing Aarons sons for not burning the right incense. Killing a man for picking up wood on the Sabbath. Yet Jesus preached reasonableness and aplying the spirit of the law.
The OT god sanctioned killing, taking revenge on enemies, yet Jesus taught to turn the other cheek and be forgiving.
OT god said it's OK to have slaves, beat them up (as long as they don't die within 3 days) Yet Jesus preached humility.
The OT god sanctioned poligamy, kidnapping women and rape (Deut chaps 20-22) Yet Jesus preached the golden rule of doing unto others...
OT god blessed his servants with wealth yet Jesus preached a simple eye.
It is very traumatic to accept the reality that what we have been taught to believe all our lives was just fables and myths. So our confirmation bias kicks in and many dismiss or ignore the reality that the Bible and all religious scripture for that matter is the invention of imperfect men. The contradictions are too glaring.