Did you try my suggestion to download the installer file using the App Store? If so, did you quit the installation and make a copy of the file? As far as I know, the latest version of macOS 14.5 is build 23F79. After you have downloaded and copied the installer, try rebooting in Safe Mode. You should find the installer in your Applications folder. Launch it from there, avoiding the update procedure from System Settings. The download will probably work in Terminal as well.
However, I do agree with your experiences with Sonoma 14.5. In my case, numerous problems arose and several attempts to downgrade to version 14.4.1 were just problematic. I finally decided to try macOS Sequoia 15.0 at beta 1. Were it not for the troubles with Sonoma, I would never have considered using a first version beta on my main system. Fortunately, it is now working better than I imagined, aside from a few quirks which are mainly from third-party apps’ incompatibility with Sequoia.
It’s working well for me, but I don’t recommend it to others. By the way, I’m now running the second beta version of Sequoia, build 24A5279h. Better and better. (Redundant backups are a must!)