Wireguard mtu setting

I managed to create wireguard server in Google Cloud (gcp) to have access to Netflix US. The only problem of using gcp is that the mtu value is limited up to 1380 only.
I am using GL AR300M running v3.22 firmware, and the wireguard mtu is set 1420 by default. I have to do “ifconfig wg0 mtu 1360” on every reboot because the default value will not work (no internet). I have tried to find uci command to set mtu for wireguard but still couldn’t figure out the working one. Is it possible to add “mtu = 1360” in wireguard config just like in ubuntu or android?
Please suggest the best way to do this

Try ‘uci commit’ to save changes to filesystem…

I remembered to do that, but I am not sure which uci set that needs to be excuted before doing that commits

After this command to save new mtu value.

Ifconfig command will work without doing uci commit, and they have different implementation with same effect to the system.
I can do ‘ifconfig wg0 mtu 1360’ but I don’t want to do it everytime the router reboots. Since putting that line into startup script don’t work, I asked what is the uci set command to change the wireguard mtu so that I could add it into startup script.