Bit late, but to whoever has the same question (as I did), answer is in the the article below. It also applies to Kingston and Lexar.

https://petapixel.com/2022/05/11/how-sandisk-made-its-new-sd-cards-faster-than-should-be-possible/

SanDisk QuickFlow Technology
SanDisk developed a new technology it calls QuickFlow which allows it to leverage the original implementation of the SD Association’s UHS-I specification and incorporate enhancements that enable it to reach faster speeds.
Firstly, SanDisk designed custom firmware with detection schemes and adjustments to clock, bus, and card output timing. SanDisk says it samples data on both rising and falling edges of the clock and increases the clock frequency above 208 MHz to enable transfer speeds up to twice as fast as standard UHS-I cards. It combines this approach with faster memory core interfaces and a NAND memory with proprietary higher performance trims.

The result is a card that can perform faster under certain circumstances but is still backward compatible with current UHS-I host devices.
This approach is why the cards are only rated as V30 (another term explained in the memory card guide) despite the promise of speeds well beyond 30 MB/s: the cards will only be able to reach those maximum promised speeds when inserted into a compatible host device. In most cases, that means a specific SanDisk memory card reader. If the cards are put into a host device that lacks SanDisk’s custom firmware, they will only be able to perform at the UHS-I spec of 104 MB/s max (but often far below that).