How are values of metrics Disk IOPS and disk queue depth correlated to tier size

I want to understand the deeper meaning of Disk IOPS and Disk queue depth metrics because I want to create alerts to be notified about unusual or excessive disk usage. I used to use disk utils metrics but they are deprecated now.

How can I find out what the value/size is of Disk queue depth of storage that this tier uses. I mean, how do I know what Disk queue depth hardware feature value is for an allocated tier?

How to find our max allowed iops for specific tier?

Then I would compare this with the values of the Mongo Atlas Disk IOPS and Disk queue depth metrics.