RAID 0 is simple to setup but effectively doubles the risk of data loss if either NVMe drive fails. By using LVM instead, you can add both drives as physical volumes in a pool. you could limit each logical volume so that it is located only on a single NVMe, which reduces the risk if one NVMe would die (only the affected volumes are gone). But as backups should be done anyhow, one could also go with RAID 0 that can double the performance.