default or selected kernelversion does not have config value CONFIG_MMC_SDHCI_UHS2.
Result is shown for kernelversion 6.6.76

UHS2 support on SDHCI controller

modulename: sdhci-uhs2.ko

configname: CONFIG_MMC_SDHCI_UHS2

Linux Kernel Configuration
└─>Device Drivers
└─>MMC/SD/SDIO card support
└─>UHS2 support on SDHCI controller
In linux kernel since version 6.13 (release Date: 2025-01-19)  
This option is selected by SDHCI controller drivers that want to
support UHS2-capable devices.

If you have a controller with this feature, say Y or M here.

source code: