You shouldn't worry about this. Unless there is some kind of hardware problem on the mac, a regular install prosedure will not crash. And should lightning strike and screw it up, you can just try again. (A failed install will result in the mac booting to the recovery partition and you will have the option to install again). A standard update erases the system volume, creates a new one and installs the complete system. Simply go to System Settings in the apple menu and choose to "Upgrade now", and the latest version of mac Sonoma will be installed. All your files and settings will be untouched, as they are on the sparate " - Data" volume.
Be aware that the process may seem erratic, with multiple startup chimes, apple logo showing, not showing, progress bar not moving, perhaps even periods of black screen. Be patient, after an hour or two, you shold be up and running.