Missouri probably has the two senators of the same party that their base has the most different opinions of. The Republican base is outright distasteful of Blunt even though they'll vote for him in a general, but they love Hawley. I suspect only Kentucky and Utah have comparable dynamics.
Are you suggesting that Lee is more popular than Romney in Utah? At this point, I wouldn't be surprised, given the toll which Romney's conviction vote regarding Trump's impeachment has taken on his reputation with the Republican base. I have no doubts that Paul is more popular than McConnell in Kentucky-for very obvious reasons.
Yes. Even in Utah, The Republican base really does not like Romney and could easily toss him out in a primary if he were to run again (I don't think he will).