The Asustor AS5304T gives you NVMe for both caching and storage

The AS5304T takes 3.5-inch and 2.5-inch SATA drives in its main bays, but also includes two internal M.2 NVMe slots that work for either caching or full storage. That flexibility sets it apart from Synology’s cache-only approach — you can actually use those NVMe slots for data.