'A long way out' is usually used in reference to distance, especially as from someone standing on a shore and talking about a ship in the water. The ship is seen as being very far from the shore.
"The ship is a long way out. It won't be here for hours."
'A long way yet' can be used in reference to distance and manner. When travelling, it means that you have many kilometres to travel before you reach your destination.- "How much longer?" "We have a long way to go yet."
Your example sentence uses 'manner' so you need to use, 'a long way to go yet.'
It means that more progress in that particular area is necessary before you achieve success.
Notice that I put your phrase in a different order. I placed the infinitive'to go' inside the phrase. This is more natural sounding.