Original post by: Chinarut

Text:

guessing you've already resolved this...

You install both drives & "fuse" them together (I recall doing this in Terminal) - it completely wipes both drives and formats it making it look like a single drive.  Then you install macOS to it & macOS manages what to "cache" on yr smaller (and faster) NVMe drive because you use these files often (most likely macOS boot files)

Status:

open