I realized … yet again … I am a complete dumbass. Guess what I should be using instead of the 6gbps SATA port?
The 40gbps Thunderbolt 3 port! This baby, right here:
Yeah, that was really stupid of me. 
SSDs aren’t that much slower, but good lord – a quality NVME drive connected via Thunderbolt 3 is pretty much full bandwidth! Like having a second M.2 PCIe 4.0 port on the motherboard!
I’ve recalibrated my two NUC10i7FNH plotters so they are both using the TB3 port to run half their plots. Gosh, that was dumb of me. You don’t even need the SSD drive mounted in there, unless you want a speedy dump drive…
I think I got distracted by “things that are directly connected to the motherboard must be faster” but that is not necessarily so in a world of USB 3.2, and Thunderbolt 3 … and the upcoming USB 4 that smooshes it all together into one giant ball of awesome!