macOS Sequoia 15.7.5 update broke my Mac mid-upgrade — login screen keeps flickering, graphics are messed up

I updated macOS Sequoia to 15.7.5 on my Mac, and this was not a clean install. I was doing a normal update while keeping my data intact.

At some point during the process, something went wrong. After that, the graphics started breaking, and now the login screen turns on and off periodically. It looks like the system is stuck in a bad state after the update/patching process.

I am not fully sure whether this was caused by the update itself, a patching issue, or something that happened during the install, but the machine was working before this.

Has anyone dealt with this kind of problem on Sequoia 15.7.5? Any safe recovery steps would be appreciated.