Here is my attempt at a 3-0-1 map like I said. I also tried to have road contiguity in all districts; if you allow districts with no road connection it gets quite a bit easier. I however did not consider incumbent residences so this probably would not work.
https://davesredistricting.org/join/ab10c7fd-a605-455e-b69b-ffbad4721959Salt Lake city inset:
Of course if you do think that non-Trump Republicans would overperform easily this could be considered a 4-0 map as well, even if it is not the most efficient one
UT-01: 48-21 Trump; Romney+44, R+26
UT-02: 49-28 Trump; Romney+30; R+20
UT-03: 45-24 Trump; Romney+39; R+24
UT-04: 41-36 Trump; Romney+16; R+11
If I had to guess, I think Republicans will likely go for 3-0-1 in Utah? Utah is probably not republican enough anymore for a proper 4-0; and there is also no need to concede a full sink to the Dems. 3-0-1 seems like the likeliest option (indeed that is how the current map already behaves in practice, though I'd want to see the Trump vs Biden numbers by CD).
What do you mean? Non-Trump Republicans can still win SLC (See Romney, Cox). I don't see why the GOP wouldn't aim for 4 seats by carving Salt Lake City even further.
My guess is that a 3-0-1 map probably transforms into a proper 4-0 map if Republicans "go back to normal" electorally. Though haven't plenty of dems won the UT-04 district, even pre-Trump?