I adjusted the size of the first firmware file "openwrt-19.07.10-brcm63xx-generic-96358VW2-generic-squashfs-cfe.bin" to the size of the original one from them, but alas, the same errors when loading into the router
So it is provider customized device rigged to not accept tplink firmware.
You need to compare TPL and ISP firmware and make guesses towards their differences.
I successfully installed it on the TD-W8950N v1, using the guide from https://openwrt.org/toh/tp-link/td-w8960n_v5. There is a link to https://github.com/wryun/openwrt/releases/tag/23.05.4-with-w8968v3, and when installing via the CFE web (http) server, everything was successfully installed and works. Issues: DSL does not work (but it doesn't work on all modems by default), LED lights are not fully displayed (possibly requiring configuration), and WiFi is slow (but it works right away). The device has a BCM43131TKMLG CPU, Winbond 25q64fvsig 8 MB Flash, Etron EM6AB160TSD-5G 64 MB DDF, bcm43131tkmlg WiFi chip. I've been testing it for several days with no crashes, and it is very stable.