Upgrade SSD: Dell XPS 15 9550 1000GB HDD 32 GB SSD

Hi, I have a Dell XPS 15 9550 1000GB HDD 32 GB SSD and want to upgrade the SSD which is currently only used for cache from what I know. I bought the Samsung 970 Pro NVM m.2 port. I plugged it in where the 32 gb ssd used to be but windows doesn`t recognise it. The device-manager recognices it but I can`t use it. I think I need AHCI mode in the bios instead of the current raid on. But I`ve heard there can be problems with just switching it. I wanted to just use Samsung Data Migration to copy the OS from the HDD to the SSD. Now is this even possible or sensible with my hardware set up? Can I mabye just change from Raid to AHCI or do I need to install windows new on the ssd?