Hard disagree. In this day and age, a device or OS that is merely 8 years old should be able to function! Is the issue limited to Lets Encrypt? If so its usage should be discouraged.
The lack of OS updates happen to correlate with hardware age for Android phones.
That's also the reasonable place to apply pressure, to the people marketing devices with minimal future support, which means they quickly become insecure.
Dumbed down, the problem is that someone the old device never heard of, is not trustworthy.
Of course, an OS should still work after 8 years. But the problem is, that the OS has been abandoned (by the device manufacturer and possibly the community), so it is falling apart. Anything that accesses the internet needs regular maintenance to not become a security hazard.
There's no need to worry about this. If the scheme in the OP works, then the same trick can be used indefinitely until such time as the Android versions in question become completely marginal, be it 4, 40, or 400 years from now.
Don't buy combination smoke & CO detectors.
Smoke rises, so detectors are best placed on or near the ceiling. CO sinks, so detectors are best placed a few feet above the ground.
Considering the importance of early notification of either condition, these requirements appear irreconcilable.
[1] https://support.firstalert.com/s/article/Where-to-install-CO...