Is it possible to debug an Arduino-IDE produced hex, bin or elf file (in this case concerning a Blue pill) ? Watching the registers and single-stepping through the code)? Which software to use on Windows 10? An ST-link v2 is available.

[Ggast]

..

[Piranha]

Even if that's possible, what's the point? For debugging purposes you will use some more or less decent IDE, which at least have debugging capability. So why then continue using that kindergarten IDE at all?