Take a look at Start/stop wireguard by shell
Maybe it would be easier to write a script around the two tasks for stop or start. Something like this should to the trick:
Stop WG
# /etc/init.d/wireguard stop && uci set wireguard.@proxy[0].enable=‘0’
Start WG
# /etc/init.d/wireguard start && uci set wireguard.@proxy[0].enable=‘1’
If you’d like to choose/change the configuration I’m afraid you have to rewrite the init-script.