What polling I've seen suggests that Trump still holds (lessened) sway within the GOP, but there are a lot of difficulties judging the meaningfulness of polling this far out from the next election cycle even in the best of cases, and current conditions do not represent a 'best case' scenario for pollsters. Things to consider:
First, Republicans are still in crisis after the events of January, making attitudes fluid. The ideology/mythology surrounding Trump has run up against reality is some seriously jarring ways: the (for most people) unexpected violence on Jan 6, Trump's implicit concession by leaving the White House, the various expected outcomes that simply did not materialize (proof of voting fraud, martial law, retention of congressional control, action by Pence or state legislatures, the 'righteous' removal of Biden by other means, etc). Many people are still clinging to the Trumpist worldview, but that worldview is producing a tremendous amount of cognitive dissonance, and cognitive dissonance on that level usually leads to schism: some die-hards will double down on the original vision, while the less committed will start to deflect, deny, and depart (note the numbers of capitol rioters and far-right groups who have explicitly stated they feel betrayed by Trump, and rejected his leadership). Whether or not Trumpism will still have the influence needed to alter Congressional races two years from now — after an ongoing drain of those who flip away from an increasingly disturbing and losing position — is an open question.
Second, Trump himself is notoriously transactional, and has never shown any indicators of long-term planning or loyalty. In two years time, Trump may decide it's in his personal interest to back Cheney and toss Greene under the bus, and those who are still influenced by him will follow suit. Trump may even decide that he is sick of actual politics, and turn his influencing capabilities to other avenues. So even if polls suggest that significant numbers will remain loyal to Trump, it isn't at all clear that Trump of 2022 will have any political continuity with Trump of 2021.
Third, a lot rides on Biden's first 100 days. Trump based his politics on the exploitation of grievance; Biden's agenda is largely (though subtly) aimed at removing the grievances that Trump exploited. Note, for example, how he talks about revitalizing communities that have traditionally been dependent on the fossil fuel industry by bringing in green-tech jobs, making an outwardly progressive policy point attractive to a significant section of the GOP base. If Biden succeeds in removing those grievances, Trump's style of politics will lose impact (at least outside of certifiably aggrieved groups, like white supremacists and conspiracy theorists). Biden (I think) is counting on the fact that most people, most of the time, just want good prospects, and that giving them those prospects will ease a lot of political tensions.
