wcs2228
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The GL-AX1800 is based on an older version of Openwrt, which may not have those packages. The lsusb command is in the usbutils package, which would displayed everything that is connected via USB to the router.
For EXT4 format, you have to install kmod-fs-ext4 package, if not already installed. For exFAT, you have to install kmod-fs-exfat package, if not already installed.
As a test, you can just reformat the USB flash drive to FAT32, which is the most common.