Upgrading SD capacity

If I have a built-in capacity card; meaning no external micro SD slot, may I use the USB slot to use for storage; using a USB adapter that has a micro SD slot? Will the aosubase read/write to this? If not, does anyone know if the standard 32GB uses dedupe and compression to fit more space? It seems 32GB would only hold a day or two of recordings, on four cameras. The paperwork says much more, but I question that. I appreciate any expert input or input from experience. Thank you.

Following the conversation as well…