I'm not looking for performance gains but only for a durable system configuration...
So, why not having a separate Sata-SSD like me with a windows loaded
(or a Windows To go on a stick), then go AHCI and boot from one of these.
Then you can upgrade your Firmware or adjust your OP...
when everything is fine, you switch back to RAID-mode and boot normally via UEFI to your NVMe SSD...
Giving you this hint, as I did it that way today