MacBook Pro stuck on "installing on Macintosh HD”

MacBook Pro stuck on installing latest Catalina update , been stuck on "installing on Macintosh HD About 40mins remaining..."

i previously had issues with Catalina but rebooting in safe mode allowed installation to work

i have tried to reboot in safe mode this time but it didn’t work, and i have tried forcing shut down and restarting. When the system boots back up it goes straight back to the installation page.

if I hold down shift to start safe mode the dialogue comes up “your Mac shut down because of a problem...press any key”

when I do this is goes back to installing once again, but never progresses.

i can’t force quit or command + control + eject or conmand + option + esc

completely unresponsive other than the power button.

i have tried contacting apple support but cannot do this as I only have the serial number available via “about this Mac” Which I obviously can’t access at the moment.

any help or fixes that have worked for those with similar issues would be greatly appreciated!!