ROCK PI 4 WiFi is not OpenWrt supported yet because the firmware 43456 is not available in the official linux firmware, has been submitted upstream and not accepted for licence issues. https://lore.kernel.org/linux-firmware/CAMEGJJ2XYvGEekfLzjL1KE6VUF-71s+S8RbJ1DuBkYU98F9nsg@mail.gmail.com/
You will need to build your own firmware to get the WiFi working,adding this 2 patches
https://github.com/mj22226/openwrt/commit/78ab00450c2a0f12ceb190cb1dbddc6306abecfe.patch
https://github.com/mj22226/openwrt/commit/6db223c41ceb9ab4b424b81c01779609d5f038e8.patch
Testing build:https://www.dropbox.com/s/i8dl8mkltg0btr9/openwrt-21.02.2-rockchip-armv8-radxa_rock-pi-4-squashfs-sysupgrade.img.gz?dl=0