To view the curves in the Graph Editor in Spine, you need to ensure that the visibility dots for the graph rows are enabled. These dots control which curves are visible in the graph. If the graph rows are hidden, you won't be able to see or control these visibility dots. You can unhide the graph rows by adjusting the view settings in the Graph Editor. Additionally, make sure that the keys you want to view have been set to Bezier, as this will allow you to see and manipulate their handles in the graph. If you are using Spine 4.1 or later, you can also use the Curves view, which provides a different way of viewing and editing curves between two keys.

For more detailed instructions, you can refer to the Spine User Guide on Graphs.

It seems like you have a filter active in the graph view:
https://esotericsoftware.com/spine-graph#Filters
The visibility dot for the target bone in the graph view is also disabled, which may contribute to not seeing anything.

Tip: you can right click the filter icon to toggle it on/off. It's red when the filter is on.