iPhone 16 battery drops by 8-10% in 24 hours while suspended

What do you mean by suspended? If you mean the iPhone is not in use, then yes it's normal for the battery to drain a bit as many background tasks still have to run, in addition to processing notifications and updating widgets etc. If you mean the iPhone is powered off, this can indicate self discharge with the battery, which would require servicing and possibly a battery replacement at the Genius Bar.

The amount of battery drain depends on how you define ‘suspended’.

If your iPhone 16 is idle (screen off, not in Low Power Mode, not charging, and no active apps running), then 8–10% battery drain in 24 hours is normal.

Not sure what you mean by "suspended". Details?