Please provide a very clear image of the flow run, pointing out what is failing
The error is super specific, its telling you that you are passing a String instead of the Object, IN whatever action is failiing.
So you need to show the specific flow, where it fails, go to the Action that is failing (in this case Create File) and show us what you are passing, as I cannot see that in the blurry picture. And while French is no problem, what I cannot do :-( is guess what the stuff is inside the actions.
I have no idea what you are talking about related to Dynamic content lost, that error isn't about it being lost, its about you passing it the wrong information.
Can I suggest you do this.. for your own sanity sake.
Create a new flow (and this is aside from the fact that you need to share the failed flow, with the action open, showing row inputs and outputs). This will tell us what you really passed in. Also the expression you are using.
Turn off this flow
In your new one just do the Get Attachments and loop...
Then add in your create file (without any other actions)
Then add your action back, if the same thing happens then its something you are doing :-(
