Those categories are usually derived from another advertised number: Drive Writes Per Day.

As an example in this Micron product brief the Latency for the read-intensive vs mixed use product are the same: https://assets.micron.com/adobe/assets/urn:aaid:aem:e71d9e5e...

Of course the footnote says that latency is a median at QD=1 random 4K IO.

From the paper the PM9A3 which is 1 DWPD has better P99.9 write latency under load vs the 7450 Pro (3 DWPD mixed use).

The best way to spec a storage system for any use case is to give baseline numbers for the desired benchmark (plus its parameters), and let the vendors do their tests in house and spec the system out to you.

If you can borrow systems, you can do it yourself, too.

Otherwise, there are too many variables to calculate now. In the past it was easier. Now it's much more complicated.