The reason I asked to see a Disk Mgmt screenshot is that other managers show the System Active boot labels differently. Judging by the screenshot of whatever manager you posted SSD is booting from C and SysReserved isn't even Active on it. But it could be inaccurate and needs to be seen from Disk Mgmt.
If you're saying that when you disconnect the RAID the SSD won't boot then you need to back up data from RAID to do that, mark System Reserved on SSD Active, then run Startup Repair - Run 3 Separate Times
to write the System Boot files to System Reserved, until it boots and shows the System Active flags on it, with Boot flag on C as seen from Disk Mgmt. Partition - Mark as Active
I would offload the files from the RAID, unRAID it in RAID controller if necessary, change to AHCI mode to test SSD performance, move SSD to DISK0 to avoid future problems (keeping it set to boot first in BIOS setup) then plug in the other HD's to use for data, wipe them if they interfere with Diskpart Clean Command
to partiton and use for data and image storage.