Make sure you have a Wf-Fi connection as it's apparently causing problems for many users to download the update. Samsung may have to pause the rollout again.
Samsung S24U in the UK I've installed 2 one UI 7 updates now, and both have been installed correctly. My phone is like new again. All you need to do is back up your phone before installing the first update. Then Clear Cache Partition. After which, any further updates should be fine.