I have done this already as it was mentioned by you in OpenWrt 19.07.2 service release. I've removed the *-ct version and downloaded the correct packages with wget on a connected device and scp'ed them to the router, installed via okpg install packagename. It was https://downloads.openwrt.org/releases/19.07.3/packages/mips_24kc/base/ath10k-firmware-qca988x_2019-10-03-d622d160-1_mips_24kc.ipk and https://downloads.openwrt.org/releases/19.07.3/targets/ath79/generic/packages/kmod-ath10k_4.14.180+4.19.120-1-1_mips_24kc.ipk
Still: opkg on the router fails with the above errors, I am not even close to start setting up the mesh network.