Thanks for posting and a big welcome to the Community 😄
Sorry that you'r getting poor speeds while using your Asus router. If the correct speeds are reaching your property, then it does suggest the issue lies with the equipment. We can see from your direct hard-wired test that 383Mb is achievable. I don't have much experience with the Asus routers, but I'll leave your thread open for other members to comment.
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