One problem with UTC everywhere is that Europe would be advantaged by having days that change during the nightly inactivity. It is easier to plan with. Other continents would switch date during the day. This would be perceived as "timezone colonialism", imposing the time that is convenient to Europeans at the expense of making it confusing everywhere else.
So nobody would be willing to accept that. If a single timezone were to be imposed over the world there would be unending debates as to which timezone should be used by all, everybody trying to explain why "my timezone is better than yours".
One more egalitarian option would be to use sidereal time, the time according to the stars. It would look like the timezone shifts continuously around the clock over the year. If noon is in the middle of the (solar) day in summer, then it will be in the middle of the night in winter. Every region on Earth would enjoy a couple of months where the solar day aligns with the calendar days.
I am not sure it will actually help to reduce confusion. Actually I am sure it will not help to reduce confusion. Think of training schedulestrain timetables! But it is egalitarian. If one time should be adopted by all it could be well that sidereal time gets the least opposition, along the lines of "if it gets messy for me, I want it to be messy for everybody".