2011 iMac stuck in reboot loop

Hi,

My iMac is a mid 2011 21.5 inch iMac. Recently it’s been stuck in a reboot loop, where it starts up and loads like normal until the sign in part, at which the computer instead shows a white screen. At this point, it then restarts and goes through the same process. I already tried safe mode, command-option-p-r, command-r, but they either have no effect or cause the screen to stop rebooting and stay at a white screen. Safe mode and command-r result in longer start up times too. Internet recovery stops working at the point where I should see the utilities menu and turns into a white screen. Are there any other solutions that I can try? Thanks.