I cannot fully agree with "Mail".

A data transfer of 315 GB and 60.02. files took 1 hour 53 minutes with the Ultra via USB-C and 1 hour 56 minutes with the "normal" WD My Passport. So the speed is not decisive for the purchase decision.
Interestingly, WD support was unable or unwilling to provide any specific information on this topic when asked in writing.

For me, the WD My Passport Ultra 5 TB is clearly superior to the "normal" WD MY Passport 5 TB in terms of speed. A Timemachine backup of 3.7 TB takes about 20 hours with the Ultra, and 12 days (!) with the "normal" one.
I own two of each and have had the experience described above with all of them.
On the one hand, this may be due to USB 3.2 vs USB 3.0, but that alone cannot account for the entire difference in speed.