I upgrade both drives PCIe/NVM & HDD to SSD's

Hello You are a Great Thanks for the answer.

As I said Before I upgrade my iMac 2017 5K Fusion Drive myself.

Upgraded with Samsung NVMe M.2 1TB SSD blade drive with adapter and Samsung 1TB SSD. it worked great but unfortunately yesterday while I working with Premier Pro (WireCast was also ran background)

My Mac suddenly restarted. I haven't had pervious experience like that. why it happened?

Should I changed everything back to a Fusion Drive. I have to do 10 hour live steaming in coming up week.

Please help me and please tell me should I install Mac OS NVMe plate or Samsung SSD. at this point I have install Mac OS in both Drives, and at the Disk startup I have chosen Samsung SSD. so I normally log in with SSD but when I install adobe software I have change custom location to NVMe SSD. Is it wrong. please tell me which is the better way to keep these 2 SSD's.

I think you are expecting too much with the M.2/adapter setup you installed. This setup has known limitations and your work flow is too intense for it, I really recommend you get the proper Apple blade SSD or go with the OWC which is a full match of Apples custom interface Vs an incomplete matchup as you are trying to force fit via an adapter something that was not designed to work in your system. Here's the proper Apple SSD SSPOLARIS or you could go with the OWC drive which is a proper duplicate of Apple's design OWC Aura Pro X2 SSD unlike the M.2 SSD with an adapter which is a force fit setup and not very reliable!

OK, lets move on... I can't make heads or tails on which drive you are running as the boot drive with your dual drive setup (Not a Fusion Drive any more!) I don't recommend Fusion drives and setup a dual SSD Fusion Drive is just wasteful! And besides you are in fact doubling the I/O flows needlessly.

I would setup only the PCIe blade SSD as the Boot drive (only one with the OS), placing on it the applications and only have the active work piece, leaving a good portion of the drive unused. Thus, you are giving your OS and Apps some breathing room so Virtual RAM, Caching, and Application Scratch space needs can leverage this space. Your other projects work or media files (music/vids) all sit on your slower SSD (SATA).