HI my name is Tamir, Im a microsoft user like you. i understand you having issue with Overtype. I was able to do some research on this and see if there was a way on my computer and unfortunately there is no way to permanently disable it without using the Insert key or using with in a word docs. here are the steps
Word Doc:
Turn off overtype mode:
Click File > Options.
Click Advanced.
Under Editing options, clear both the Use the Insert key to control overtype mode and the Use overtype mode check boxes.
Insert KeY:
If you press the "Insert" key or "Ins" (located to the right of the Backspace key) once; you can change your computer to Overtype mode. When your computer is in Overtype mode, the text you type replaces any existing text to the right of the insertion point and erases it. Press the "Ins" key to toggle overtype mode off.
The other way is to disable the insert key but like you mention you use it all the time so it defeats the purpose. Or remapping the keyboard for each app.