Doubts in for user widgets

for now i using blueprints to make my game
when i past to c++ code i have to create a userwidget for every widget
for example the inventory widget i have create a userwidget class to inventory widget

You may not need to move widgets to C++. You can add components into your widget that are C++ based and whose certain functions are exposed to Blueprints. Then, in your widget event graph, you can call these components in order to link data to your widget UI (like updating a counter or so). This way most of the logic and code will be in C++, but only the interface with the widget items will be in Blueprint.