Fwiw the iPad 7 has an A10 Fusion processor and 3GB of RAM, and it supports iPadOS 18.
I have a 2nd Gen 12.9" iPad Pro with A10X 2.3 GHz. It has 4GB of RAM and Power VR Graphics Series GPU with 12 cores. My Mum has the same specced 10.5". Both released 2017.
The iPad 7 has an A10 Fusion also 2.3 GHz with just 3GB and the GPU has only 6 cores and is also a PowerVR Series but with the extension 7XT Plus.
I am sure the Pros are faster but only the iPad 7 is getting iOS 18. Only reason, it had been released two years later.
It seems they just dropped everything older than 2019 and only kept the iPhone XS and XR from 2018 to drop 17 for iPhones completely.
It doesn't make much sense to keep three iPads on 17, they could have dropped that version completely there too. Without Apple Intelligence it feels even faster.
The only reason for keeping the two Pros on 17 is because the iPad 6 from one year later only has 2GB of RAM, but the same CPU, GPU and cameras as the iPad 7 that only got 1GB of RAM more and eSIM support.
For me this is just planned obsolescence for. I won't buy a new Pro anyway.
I got a used 2019 Air and 2021 iPad 9 in perfect condition for very cheap instead.