Can you try using the following image, rename it to openwrt.bin
https://downloads.openwrt.org/releases/22.03.3/targets/lantiq/xrx200/openwrt-22.03.3-lantiq-xrx200-tplink_tdw8980-squashfs-sysupgrade.bin
Can you also run all the commands from the wiki in the tftp + serial section
Eg
// Set temporally the IP address for the router:
setenv ipaddr 192.168.11.13
// Set IP address where the tftp server is listen:
setenv serverip 192.168.11.220
setenv bootargs 'board=WD8980'
// Retrieve the OpenWrt image
tftpboot $(loadaddr) openwrt.bin
// Erase old image and write the new one to disk and reboot:
sf erase 0x20000 0x7a0000
sf write $(loadaddr) 0x20000 0x$(filesize)
reset
Adjusting IP addresses where appropriate
Can you describe what cables you have connected to your router and what IP your computer has? Just confirming you have the correct setup.