The cause of The future is now: opkg vs apk - #127 by ka2107 issue was https://github.com/openwrt/openwrt/issues/16953
# cat /etc/apk/arch
x86_64
which has been fixed by https://github.com/openwrt/openwrt/pull/17015
Now it is
# cat /etc/apk/arch
aarch64_cortex-a53