The Acer Aspire XC-1785 supports both PCIe and SATA SSDs as additional drives. You can therefore install an NVMe SSD (M.2 PCIe) or a SATA SSD, depending on which interfaces are available in the housing and how the internal connection is designed.

There are reports that users have successfully installed a Samsung 4TB SSD 990 EVO Plus (NVMe), for example, although drivers may be required for larger SSDs.

For optimum compatibility, an M.2 NVMe SSD in 2280 format is recommended, as this corresponds to the standard supported by the system.

To summarise: You can install an additional PCIe NVMe M.2 SSD or a SATA SSD, whereby M.2 NVMe SSDs such as the Samsung 990 EVO Plus or Kingston KC600 are well compatible.