Like @alzhao said, performing configuration of the router from the WAN side creates security vulnerabilities. There are ways to do it, but if you aren’t going to spend the time to learn how to harden your router, you probably should just avoid doing this. This is one of those times that the OpenWRT gurus are trying to protect us from ourselves!

[As I understand it, your issue is with OpenWRT, not GLI.]

If you really want to do this, start by taking a look here:

https://wiki.openwrt.org/doc/howto/access.modem.through.nat

But, really, since you have your AR150 in your home network, when you want to configure your AR150, just connect to the AR150’s SSID as a WLAN client and then point your browser to the AR150’s LAN address. Or just connect a wire to the LAN port of the AR150 to your computer, if that suits you better.

Let us know how it goes!