How to reinstall / repair Debian after a failed upgrade?

I followed this wiki tried to upgrade Debian 10 to 11 then 12, but for some reason some part messed up the system and now it can't boot (kernel panic) and entire system is messed up: no apt available, no vi available etc. I am trying to use Debian 12 installer to repair it, trying to use its rescue mode to reinstall OS. What I tried was: 1. Boot rescue mode with boot disk and try to install minimum dependency like apt but it doesn't work. Too much dependencies 2. I am also working with the debootstrap to reinstall the target disk, but that too got stuck at "Chosen extractor for .deb packages: ar" and failed. What is the best way to reinstall and/or repair this entire Debian OS and make the old OS working again?