Great.
I found an image I compiled as such that I couldn’t access earlier.
For anyone else who experiences this problem, be sure to update the image on SPI-NOR, even though booting from another medium:
Image to flash to SPI-NOR flash: u-boot-rockchip-spi-rk3588-rock5b.zip (624.8 KB)
That should fix booting from any source, since the ddr binairy will be loaded from spi-nor if present.
Just for anyone interested, here is the other image:
Image to flash to SD / EMMC: u-boot-rockchip-rk3588-rock5b.zip (633.7 KB)