Then this is my written proof that I think this chip will not be an M4, but also not an M3. No guess to naming though
I always found it odd for Apple to simpy re-use the Mac chip for iPad. One of the major benefits of designing their own chips, is the ability to customize the chip for the particular purpose. I think the M1 and M2 in iPads were a stop-gap solution, until they were ready with a chip designed specifically for iPad. Like others have pointed out, iPad sells in higher numbers than Macs. It doesn't make sense to have the iPad be compromised to piggy-back off the Mac chips.
It could even be the hint behind the "let loose" moniker. The iPad is finally ready to cut the leash, and be it's own thing rather than being tethered to either the iPhone or the Mac. The first step was iPadOS, now it's time for the CPU.
I don't have enough insight to make an educated guess as to exactly which chip layout makes more sense for the iPad, in terms of core counts etc. I do believe it will be M3 technology though, and not the premiere for M4.
Curveball: They might even release it in two variants (Pro and non-Pro obviously), to differentiate the Air and the Pro. Which would explain the alignment to release them together.