Allow me to save you the trouble in waiting.
Here is what the reviews will show:
A huge increase in synthetic benchmarks, 50% maybe 60% performance increase in synthetics over 2018/2020 models.
Real world performance, (ie, render times of 3D models, 4K video, etc.) roughly 15% to 20% faster than the 2018/2020 models.
12.9" screen is "GORGEOUS" but "gets hotter than the previous panels".
Everything else is iPad Pro, it's the same as it's been since the 2018 model.
MaxTech will sh*t his pants trying to justify his endless prerelease videos proclaiming this historic in generational revision.
Everyone else, (think MKBHD) will say "Yeah, it's amazing that the M1 is now inside the iPad Pro, but it's still just iPadOS and the speed increase isn't important given the performance of the 2018/2020 models and software limitations."
Average verdict: "No need to upgrade from 2020 unless Apple has something up their sleeve at WWDC, or unless you just need to have the newest tech."
That'll do it.