Kubuntu 24.10 is no longer supported. Can you use a supported release? (the most current releases are 24.04 LTS and 25.04)
The files are still there, but your python3.12 binary that python3 points to has somehow ended up with permissions that only allow root, and only root, to run it. That is not normal. If you don’t know how that happened, who knows if whatever it is may have affected other system-critical files’ permissions as well…
With all that, the best path forward is likely to
- back up your data and system configuration,
- do a complete fresh reinstall of a supported Kubuntu version.