Xiaomi Mi Router 4A (100M International Edition) cannot install mwan3, doesnt support
Then you're not running openwrt.
Im running openwrt new version (22.03.3) on 4A 100m
then you should be able to install it, if not, post the reason why, not only "it doesn't work"
I have installed mwan3 for the Mi Router 4A (100M International Edition) running 22.03.3.
The procedure is: update the list of packages, search/install mwan3 and optionally luci-app-mwan3.
Note: when doing this from LuCI it showed me JSON errors, however the packages were installed. On the other hand, when I did that from cli, it didn't show any error, so I prefer that way.