One can be Sata but it doesnt state they both cant be pcie. Ive got several of these adapters on Z170a pc mate boards and they work. But those little boards only have a single m.2
Dont use Sata 1 if you use the m.2 per your manual.
I was planning to use both M.2 slots for two more GPU's using this converter:
https://www.ebay.ca/itm/NGFF-M2-to-PCI-e-4X-1X-Slot-Riser-Card-M-Key-SSD-Port-to-PCIE-Adapter-for-Mining/254184656176?_trkparms=aid%3D1110009%26algo%3DSPLICE.COMPLISTINGS%26ao%3D1%26asc%3D20200220094952%26meid%3D15bea48ffcb04355960085ed325a79df%26pid%3D100008%26rk%3D1%26rkt%3D12%26sd%3D193101966964%26itm%3D254184656176%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3Ddefault&_trksid=p2047675.c100008.m2219
Good to know though about the SATA limitations, almost missed that!