iOS attempted updates consistently crashes iphone with low storage

iPhone 13 with iOS 26.6. The last few updates have crashed my phone, I suspect because of low storage available. I typically have about 10GB free space.

Each time it's the same.

1. Request update
2. Update states "Cannot Download Update" and suggests managing your storage (note: this is not the offloading apps warning). Only available options are "Close" or "Storage".
3. There's no other notification, yet in the background the update is still downloaded, verified by free space disappearing.
4. Phone becomes very slow and ultimately unresponsive.
5. Phone crashes.

This was somewhat understandable with iOS 26.6 as it was a large update (3GB I think), but 26.6.1 is only ~500MB why is it saying there isn't enough space for the download?

My expected behaviour would be that after step 3, the download is no longer attempted without user input. This allows the user to delete or remove things to make space.