High Sierra Clean Install from USB after Crash with dual boot

Hello community,

I own a Mid 2011 iMac 21.5". I had a dual boot installed with Windows 11 which was working fine for almost a year until yesterday.

Yesterday tried to boot on to Mac OS and did hold the option key as usual to select the boot in windows or Mac.

However both the OS appeared to crash including Mac recovery drive.

Every time I try booting the machine, it never asks me any option to choose OS despite trying all the options mentioned on multiple forums or even on the official apple help and support.

No matter whatever I press, the machine boots straight to Windows and ends up in blue screen of death with error code only 3 options.

Enter, F1 and F8. Of which Enter and F8 does nothing but flicker the screen as if it did something but nothing happens in real.

F1 reboots the machine to land on same display- the blue screen of death.

I have created a bootable USB with clean DMG package of High Sierra.

Now all I am seeking is how to get to the boot option and clean install Mac OS only.

Please don't suggest to visit Apple Store as I did and they suggested go for newer machine.

Thanks in advance.