Is it time to bin it?

Hey every, hope you‘re doing better than me.

After more a less an entire week of trying to install Sequoia on my 2011 1TB mac I‘m not getting anywhere anymore.

It was running Sequoia beautifully until a couple of weeks ago when the power went out due to a thunderstorm, the computer obviously shut off but wouldn’t finish staring up when restarting.

I had to erase and install and it managed to install the OS once or twice but there were significant bugs present until it wouldn’t react at all anymore.

And now I can‘t even reinstall High Sierra and am getting this error message.

I tried looking online but didn’t find anything I would be capable of doing, is there any way to fix it or is the computer cooked?

Thanks for taking the time to read!