I'm currently assembling a new pc build based around a 3700X and a 5700XT. Storagewise, there is a SATA SSD left I can use as a system drive but I am wondering what would work best with Resolve for temporary project storage.

SSD prices have come down a lot, so having a spacious scratch drive is possible. I'm usually doing commercials, so no feature lenght space requirements. With a scratch drive, I could store at least 2-3 projects at the same time.
QUESTION: Is SATA really such a disadvantage to PCI->M2 if it sustains 500MB/s read speed? 3:1 is around 185/MB/s, even Redcode 8K 5:1 is only 270MB/s, so pretty much any non-QLC-SATA SSD should do, right?

With denoising and OFX, I'm thinking one can't do without a buffer drive for render cache, right? Question again, DCI4K - DNxHR444 is only 185MB/s, so what would I do with 1800-2500MB write/read of PCI?

Is an external scratch-RAID-0 still the better option? Having 2-4 HDDs should sustain a good 300-450MB sequential read and space is totally a non-issue with this solution?

I'm pretty lost here because there's a load of possibilities with cheaper SSDs now. Any input?