Isn’t it just too easy to see from Flow (Power Automate’s) Runs what data was passed on? A simple switch in the Power Automate designer will secure this.
By default, if you have access to the Flow, you can simply go in and see the inputs
Secure Input / Output
In the Flow designer, you can select and step and go to Settings
And turn on Secure Input / Output depending on what you want. It says this is still in Preview as of the day of writing this post.
Once this is Active, it is denoted by a Lock symbol on the step you enabled it on.
And now, when you try to look at the data, it will hide away the information
Note: Please note that this will run only for the Run History records after this was turned on. The previous records will continue to show the data.
Hope this helps!!