I recommend you read time keeping on the computer systems. Without NTP and some atomic clocks on the network, computers can't keep accurate time themselves.
And using a moving window / sun synchronization like that is just brave to put it mildly.
[0] https://blog.codinghorror.com/keeping-time-on-the-pc/
Also, there was an excellent article about clock drift, but I failed to find it.
Unequal hours were a thing:
Having seen a colleague deal with northern hemisphere Guam -> Puerto Rico times, thinking about implementing the above gives me heart palpitations.
sure, except obviously sunrise at 6AM and sunset at 6PM.
From now on, sunrise is 0700. The clock runs from 0700 sunrise to whatever time necessary overnight to arrive at sunrise again, at which point the time becomes 0700. For the part of the year where that duration is greater than 24 hours, the time past 06:59 simply counts up extra seconds until reset.
Now we can have computers and every other carefully regulated timekeeping system on milliseconds since an epoch timestamp, and regular old clock time fits everyone's schedules regardless of time of year, and never needs 'adjusting' again, since its sun-synchronized.
And people said Y2K and the Year 2038 issues were hard...