General Discussion

Corbyn's policies were actually popular when polled in ways that omitted him from being identified with them: https://www.independent.co.uk/news/uk/politics/corybn-labour-policies-toxic-general-election-2019-leadership-latest-a9279946.html

I believe similar results were found in the US with some of Bernie Sanders' policies.

Now, even with Corbyn clearly identified as a figurehead for those policies, recent polling has shown that 1 in 3 Labour voters would vote for Corbyn's nascent party even before it has a name, and 1 in 5 of the general population would do so: https://www.ipsos.com/en-uk/one-five-britons-would-consider-voting-new-left-wing-party-rising-one-three-young-people-and-labour

Other polling has shown that Corbyn is currently regarded as having been a better Labour leader than Starmer is: https://yougov.co.uk/politics/articles/52935-how-do-britons-see-jeremy-corbyn-and-his-new-party-10-years-since-his-labour-leadership-victory