moonpie A good start to bisect and find out exactly why autobot believes unsupported and EOL lubuntu 18.04 is "safe." autobot can then create his own "safe" distro (autobot's Eye Safe Linux 24.10) which is up to date and share it here.
The suggestion to bisect an entire Linux distro across six years of commits is hardly practical. Bisecting the Linux kernel and/or Linux GPU drivers, on the other hand, might be worth exploring.
EOL operating systems will likely contain vulnerabilities (including serious ones), and the vendors certainly use this as an incentive for you to use their latest version. On the other hand, an OS version with eye strain is a guaranteed threat versus an OS version with vulnerabilities being a potential threat. A sophisticated user who is able to harden or lock down an older operating system, or a user with an offline workload, may be able to mitigate the risks of using an older OS version to an acceptable level, in my view.