Well, this seems not good. I tried booting it up anyway after attaching a CPU cooler, and it is indeed DOA.
Radxa ROCK 5 ITX 24GB - I bought two of them, the other is fine.
Also they're now sold out. 😭
Anyone have a functional Radxa ROCK 5 ITX or ROCK 5 ITX+ with 16GB+ of RAM they don't need that they'd be willing to sell me?