Question about ASUS RT-AX58U V2

If you want the router to "let through" directly to the Internet, you can simply set "Enable NAT" to "No" in "Advanced Settings - WAN - Basic Config". However, I have not tested it. :)

I only use it as an access point and leave the rest to another router. Is that what you mean?

I don't know, my device is connected to a separate router.