It is unified memory on this one

From the spec sheets I’m looking at, it is not. I’m seeing models of the Dell Pro Max with 128 GB of DDR5-6400 as CAMM2, then a separate memory of up to 24 GB on the GPU. CAMM2 does not make the memory unified.

There are also SO-DIMM options.

You're not looking at the right thing. Dell's naming is horrible. Dell Pro Max with GB10 (https://www.dell.com/en-us/shop/cty/pdp/spd/dell-pro-max-fcm...). It's a very different computer than what you're looking at and has 128GB LPDDR5X unified memory.

Thanks for pointing that out. I found a more informative article about that model at https://www.mcpgov.com/dell-pro-max-gb10

my bad

I took ~ to be a "singing tone" for some reason till I saw sibling and realized it might be an attempted strikethrough xD

That won't hold much benefit as SOCAMM2 and LPCAMM2 get more popular.