No one has to be pissed off, they will slowly adjust and learn. Eventually people will only think in UTC. If that never happens then, leave both times. I think over time people will develop an intuitive sense of UTC the same way we do now for timezones but we lose all of the issues with having more than one truth.

There is no way to solve that problem of Uncle Steve (imo). But there is no difference in saying Steve is +8 hours so our noon is his 20:00 and or saying we should only call Steve between 03:00 and 20:00 UTC. It is an offset either way. It is only jarring to think that way now because it is the one way people have.

There is also the problem of someone driving across the US and suddenly they pass an invisible line and now it is one hour in the past or the future. The day changing while you work already happens for everyone working 3rd shift.

Billions of dollars in waste and confusion happen today because of forgetting about timezones. One study suggests that international trade is decreased by 5% per timezone between countries.