it seems like you are creating another donation with the donate button. There is already a donation object so you dont have to create in the donate microflow. Before showing this popup you have to create the donation object. Configure a microflow for the onclick action of the list view. There you will get the charity obj as parameter. create donation object here and associate it with charity then show the popup.
Hope this helps :)
When looking at your microflow, it looks like you retrieve the charity each time you press the button. As this is just retrieving a charity, I assume that this will be random (the first one in your case).
If the button is placed on the charity page, you can use the charity as an input parameter for your microflow. You can remove the retrieve from database, so you will always use the correct charity.
Hopefully, this helps.
I tried, but its not working
so on the detail page dont use create object button if you have to then provide context using relationships so ur donation is connected to ur charity.
now on click save donation u can retrive the charity from the association and make changes to charity there.