Try with File dropper or Drop zone widget here we can able to customize as we want.
these are filled by default and cannot be changed easily as you want.
If you want to change the behaviour/experience of the user for the filemanager, you might have to check if there is a different widget that will help you such as the filedropper:
Also, from an UX point of view, the usage of the word “browse” is common for users throughout the world, which therefor could still be a good route to go.
I hope this helps.