On a Windows or macOS desktop, the OS-provided MessageBox() can be freely moved around the screen - but that's not how in-web-page modals tend to work.
I don't find I have the problem you describe, because at worst you can generally abort the save or whatever and verify then redo it.
The one that bugs me is online order forms that don't give you all your critical details like dates, and exactly what you are paying for, on one screen where you finally commit.
Then don't confirm them if you aren't sure you wanted to confirm. The dialog is here to alert that you did click on confirm and it seems to me you weren't ready yet, so it did its job.
Famous example of how badly this works is Jira. Want to look something up in another ticket? Bad luck! You need to close that ticket, then open the other one, then memorize or copy the info you need, then close that ticket, then open the original one again. At that point you are better off circumventing the whole shit UI and clone the browser tab. Which ultimately leads to having a dozen browser tabs open that one needs to cleanup later. Add to that the general incredible sluggishness of Jira, and the massive amount of things loaded when you load any of its pages, and you have a recipe for the disaster that thing is.