I remember the good old MS‑DOS use to show a block cursor in overwrite mode and a thin vertical line cursor in Insert mode.
Is there a way to achieve a similar distinction (not necessarily shape based, this may as much a colour distinction) in GNOME Terminal or in a shell ? The latter, is because I feel this may perhaps be the Shell who would have to handles this, while I'm not sure. Or maybe the TTY emulation? Finally, I don't even know which track to follow.