I think that problem might be happening because of an issue with the installer when overwriting a 64-bit version with a 32-bit version. Please try explicitly uninstalling Tiled before installing it again, which I think should resolve the problem.
Since I’ve updated the main builds of Tiled to Qt 6, they now require at least Windows 10 and 64-bit. For compatibility I’ve kept the 32-bit build on Qt 5. There should generally not be any issue with running the 32-bit version on 64-bit Windows.