RTL8881AN = Lexra architecture
See ZTE ZXHN H118Na (HW ver 2.3) - Possible OpenWrt flash for a collection of Lexra info.
In addition to the unsupported SoC, this device has also a space problem (only 4/32 MB), see https://openwrt.org/supported_devices/432_warning for more info.
IMHO highly unlikely that this device will ever get supported.