I think the idea of 9-5 being "normal" is a stereotype that doesn't stand up to scrutiny. If it was ever actually "normal", it was in a bygone era. I don't actually have anyone in my social circles who starts a scheduled morning shift after 8:00AM. Most people seem to start morning work shifts between 6:00 and 7:30. My last (manufacturing) employer had regular shifts 07:00-15:30, 15:00-23:30, and 23:00-07:30.
The only people in my social circles who might work 9-5 are people on flexible schedules, who are already free to ignore the biannual time change.
That being said, the earliest standard-time sunset in my area is around 4:30PM. Evening twilight lasts until 5:00. No daylight, no twilight for this 9-5 standard time worker.
With permanent DST, this supposedly "normal" 9-5 shift worker gets sunset at 5:30, and half an hour of twilight after that. They get at least 60 minutes of evening daylight in the darkest of winter in December/January. They get much more than that hour in November, February, and March.
Thirty minute time zones are not at all feasible.
The best solution is to permanently adopt the more widely used system (DST) immediately, then reconsider the boundaries of four (or perhaps five) zones.