Importing HiRISE Terrain Data into Unity (Via Blender)

Hello all,

I'm just looking for some tips on how best to get the Mars HiRISE Terrain data imported into Unity.

https://www.uahirise.org/dtm/dtm.php?ID=PSP_008437_1750

Currently, the data is available in numerous formats. The most accurate format is .img, which notably does not have any shadows from sunlight on it, as it is binocular, so ideally I'd like to use it, I think. There's also a bunch of jpgs and other file types that maybe some magic can be done with, but that's all above my head.

So my current issue right now is, I'm not sure how to get Blender to output a useful file for Unity to use. I would like to generate a .raw file to create a heightmap from, but I realize it is sort of the long way of doing things. And the .raw file seems like a weird bottleneck. Is it as limiting as it seems? Is the new "hole" support any good?

Some advice to point me in the right direction would be really helpful here. I do plan on making rather large levels, so I figure the hassle of making these meshes into heightmaps to take advantage of terrain culling and LOD efficiencies is worth it. Is that reasonable? Should I be asking this question in a blender forum? I will anyways, but I'm a Unity girl before a Blender girl, so I thought I'd start here first.