Adding storage after purchase

Is it possible to add storage after purchasing the librem 14?

That depends on whether “add storage” means “add a second drive” or “increase the total amount of storage”.

I believe that as it stands today you can’t add a second drive.

You can increase the total amount of storage by taking out the existing drive and upgrading to a higher capacity drive. Any standard 80mm M.2 drive, whether the drive is using the SATA interface or the NVMe interface, should work, and there are various topics with people asking about replacing the existing drive. (For performance you would prefer a drive that uses the NVMe interface.)