A simple dictionary search (multiple dictionaries) backs this up.
Comparing the SoCs of the RPi4 to the iPad Pro, the Pro's A12Z has 8 cores vs the 4 of the Pi's Cortex-A72, more L1 cache, way more L2 cache, 8 GPU cores on chip (vs the Pi's separate GPU (which has at most 4 cores)), etc. etc.
The only meaning of "oomph" which I could imagine that would put the Pi ahead of the iPad would be in flexibility in terms of what can be done with the device.
That's exactly the point.
A RPi is currently much more flexible than an iPad for some workflows that need a terminal or desktop software. For this use case, the iPad acts as a self-contained power supply, internet connection and thin client. However the iPad's own capabilities are recently improving with the new features of iPadOS.