That is almost exactly correct. Virginia's power rating is generally 4 to 5 points above Miami's, depending on which source you use. Given home field on a Saturday and Virginia would be roughly -7.
However, Virginia at home on a short week would be a larger favorite, closer to -7.5 or -8. Home teams always receive benefit of a doubt in those short week games, unless the road team had a bye the week before.
Miami at home on a short week is given benefit of a doubt. That's why the Canes are small favorite in the -1.5 to -2 range.
None of this is complicated if you follow the situational variables. In Las Vegas it is more difficult to pick winners than simply get a great pointspread on one game after another. That is a major part of it and it is one of the reasons that it is far easier to win at sports betting in that town than outsiders realize. You aren't sitting like a dolt in a chair with one wager at a standard number. If you have the proper instincts, know the right people, and do the legwork, then it is a mathematical situation of shifting small theoretical disadvantage to small advantage. Volume and an edge. Now that I'm out of town I don't enjoy those edges so my football results haven't been great for a few years. But I've done well on atypical stuff like the world track and field championships last week.
Virginia's power rating is not very high. They have been basically 30th to 37th in the country all year. Somehow the perception here has placed them far above that level. Meanwhile the ACC Coastal is condensed. That works on the high end and also the low end. Miami doesn't deserve to be much of a favorite or much of a dog.
The only exception now would be Georgia Tech. That team's power rating has plummeted and it now severely low, one of the worst I remember within the ACC in recent years. Miami would be a double digit favorite in that game if played right now. Georgia Tech's power rating is now 7-8 points below Virginia Tech.