I think that matches the RDIMM keying although that information is oddly hard to find online.
https://www.mouser.com/datasheet/2/671/ddr5_rdimm_core-3310292.pdf
Page 24 has dimensions but you have to do some arithmetic to actually get the slot center of 62.8mm and 70.55mm
So I think the kingston spec sheet has the wrong drawing that shows UDIMM dimensions.
I think you need to return the RDIMM and get UDIMM, or switch motherboards.
He's talking about campaign funds not personal finances. For law abiding candidates, those are entirely separate things.