GMKTec G3 is a very good N100 PC. It's not the smallest one and its SATA port is also M2, but its NVMe port is x2 instead of x1.

Another alternative is BeeLink's S12 series, which accept 2.5" SATA drives and M2 NVMe drives. However, the NVMe port on these systems are x1.

Both are silent (for active cooling), dependable systems, but not as silent and small as a passively cooled RPi5.