Polls in!
https://theweek.com/speedreads/870332/brutal-new-poll-shows-3-10-republicans-support-trump-impeachment-push
1 in 3 Republicans think impeachment proceedings against Trump are appropriate.
As a historical note, public support for impeachment of Nixon in the 1970s was modest (<40%) until the impeachment enquiry ended, by which time it was around 60%. Although support for impeaching Trump is currently higher than for Nixon at a similar point across the whole population, the USA is more polarised now, which may mean both that Democrats are more pro-impeachment now, and Republicans will be less likely to shift in favour in the future, so the same sort of shift may not materialise.