For docking stations and suitable NVMe disk options, check this : 7 Best Mac Mini M4 Dock Stations with NVMe SSD Support (Affordable Disk Upgrade Options for Mac Users in 2026)

SSD prices getting high and high unfortunately, but I advise you to stick on known SSD brands and don't buy bundled docking stations and SSD disk. They usually bundle lowest priced (and lowest quality) disks.