Does the QNAP TS-464 have a PCIe slot for expansion?

No, the [QNAP TS](https://www.amazon.com/s?k=QNAP+TS&tag=wehavethat-20)-464 has no internal PCIe slot. Expansion is limited to USB 3.2 Gen 2 via two Type-A ports and one Type-C port for connecting QNAP expansion enclosures.