Thank goodness for Mitt Romney being a Republican.
I hate the RINOs just like you do, but they serve a purpose. They are the only reason Trump has a GOP Senate that give us Goresuch and Kavanaugh on the Supreme Court. If all the RINOs were actually registered Democrats, Pelosi would have a Rat controlled Senate to block everything Trump wants and to control ALL judicial nominees.
Now that would be REALLY dangerous. Nuclear dangerous. I hate the RINOs, but much better to have Democrats with an R than actual Democrats who would control the Senate.
It would be much better to have actual conservative Republicans than Democrats in R jerseys.
Your assumption that those seats would be occupied by Democrats in D jerseys only holds up if the Bush League Republicans back the D jersey like they did in AL, NV, DE, IN, MO.
Bush League Republicans MUST become extinct before the Republic does.
A RINO might be thr best we can do in, say, New Jersey. But we are talking about Utah, the state dominated by socially conservative Mormons. No Democrat has won a Presidential election there since 1964. We can do better here.
It would be better to have a minority of actual conservatives and build on that base.