It's true. It's last generation's M3 based CPU instead of the M4. But the M3 Ultra has 32 cores vs the M4 iPad's 9 or 10 cores.
Apple doesn't make an Ultra version of the M4. The speculation is they'll do this every other generation.
Very high core count CPUs generally have slower single-core performance than their lower core-count counterparts.
Even on the x86 side, if your workloads are primarily single threaded then you will be better served by a consumer CPU than a $10,000 server CPU.
For heavy multi-threaded workloads there is no comparison.
I could be mistaken, but I think the mac studio comes with either an M3 ultra or an M4 max, and the ipad comes with an M4 chip. I think they decided not to make an ultra for the M4 generation, but don't take my word for it.