End term by-elections turnouts for constituencies that will not exist in their current form at the next election and for the most unpopular government since polling began is not a guide to Tory apathy, that's the narrative the Tories themselves put about
Tory apathy is rarely a thing, the Tories are the ones that traditionally do vote, its the Labour vote that is more likely apathetic (historically) hence the old idea that Labour needed good weather to have a bumper vote etc.
Hardcore nutters clearly voted, if any party got the most of their voters out it was Reform. Former Tory voters may well have been apathetic, possibly because they didn't know which way to go, come the general election, I don't think the percentages for Tory and Labour in those seats will change much