Hello @Zhifan Ye
The last version of the Windows 10 Insider Preview is the Build 19044.1263 (21H2) as described here:
The difference in the versions are the Semiannual channels vs the Cumulative update channel which often includes Servicing updates to prepare the system repository for future version rather to provide an update to the system. Meaning that if you want to download the core "build" without additional updates that is the correct one.
Information about the Cumulative update rollout: https://blogs.windows.com/windows-insider/2021/05/26/announcing-windows-10-insider-preview-build-21390/
Hope this helps with your query,
-----------
--If the reply is helpful, please Upvote and Accept as answer--