Is it possible to reassign hotkeys from an app?

Is it possible to reassign hotkeys when the user launches the app?
Let’s say there is settings page In my app, and I want to give the user the possibility to change hotkeys.

Not possible.
It can only be done through the Overwolf client settings page.
All you can do is link directly to the hotkey there with
href="overwolf://settings/hotkeys#hotkey_name_in_manifest

An alternative is to use overwolf.games.inputTracking to set up additional hotkeys that the user can change from within the app.