That's a known issue on Edgerouter X and Edgerouter Lite. I use an Edgerouter Lite and am on my third flash drive. The flash drives are just cheap USB drives, in contrast to X where they're soldered on. An industrial grade USB drive would cost almost the same as the device itself. I bought a 2 GB one but it refuses to install EdgeOS on less than 4 GB. However the device itself works well, and has three ethernet. As switch I use an EdgeSwitch 16 port, which provides PoE for the Unifi WLAN AP (UAP Pro or whatever). It all runs Linux, and I got root on the devices. Wouldn't want it any other way. Except perhaps a Turris Mox modular router or running the firewall/router on the same server as my NAS (as VM in Proxmox). But it allows less flexibility IMO. Then I would use OPNsense, Turris runs op OpenWrt. I don't want to use a proprietary OS like RouterOS or an out of date OS which is no longer supported.