The New Power Automate Designer and the old Designer are two different ways to create and edit flows in Power Automate. The New Power Automate Designer is a new, more modern interface that is designed to be easier to use and more powerful than the old Designer. It is the default designer for new flows, but you can still use the old Designer if you prefer.
Here are some of the specific features of the New Power Automate Designer:
The Old Designer is still a powerful tool, but it is becoming less supported and may eventually be deprecated. If you are new to Power Automate, I recommend using the New Power Automate Designer. If you are an experienced user of the old Designer, you may want to try the New Power Automate Designer to see if you prefer it.