The internal SSD is formatted to JHFS+ with the Mojave Installer disk utility. Previously, it had Mojave and later Catalina installed on it without a problem
Neither the El Capitan or Sierra installers see the internal SSD. Ditto for El Capitan Disk Utility and diskutil, El Capitan recovery mode diskutil. They simply don't list any internal drive at all.
The Mojave installer continues to see the SSD that the others don't. How to fix?
MacBook Air (13-inch, Early 2014) Model Identifier: MacBookAir6,2 8GB Ram
SSD: Sintech adapter card: https://www.amazon.com/dp/B01CWWAENG?ref_=pe_2640190_368227370_DDT_E_DDE_dt_1
XPG SX8200 Pro (2TB) https://www.amazon.com/XPG-SX8200-Gen3x4-3000MB-ASX8200PNP-2TT-C/dp/B07TY2TN64/ref=sr_1_2?crid=2CZKWWSKOGLJ4&dchild=1&keywords=xpg+sx8200+pro+2tb&qid=1606598480&s=electronics&sprefix=XPG+SX8200+Pro%2Celectronics%2C337&sr=1-2