I just downloaded the updated SDK, I also saw the LittleFS being added, which appears to be a much better choice for embedded devices.
I tried the simplest project (New Workspace, click New Project, select RT1050-EVKB)
Bare Metal and File System and SDMMC

When I build I get:
Finished building: ../source/semihost_hardfault.c
In file included from ../sdmmc/inc/fsl_mmc.h:12:0,
from ../sdmmc/src/fsl_mmc.c:10:
../sdmmc/inc/fsl_sdmmc_common.h:12:10: fatal error: fsl_common.h: No such file or directory
#include "fsl_common.h"
^~~~~~~~~~~~~~
compilation terminated.
make: *** [sdmmc/src/subdir.mk:23: sdmmc/src/fsl_mmc.o] Error 1
make: *** Waiting for unfinished jobs....
I also only selected the POLLED adaptor
I did try with FreeRTOS and got the about the same thing...
I do see the file in the SDK zip file, but shouldn't this me extracted me?
I have been using the SDK as a the ZIP that I downloaded from the website.
Is that the normal way to use it?
Or should I unzip it so MCUX can link to the files?
Tom