There's no need in a new artificial language. If there was a need, humans could easily invent one without any LLM assistance, just like we invented Esperanto. But there is none. BTW, English is neither the first nor the last international language. It will be (and is gradually) replaced by others.

We absolutely can invent a new language. It won't be as good as AI could make it.

For example, it could analyze a lot of data and catalog how certain sounds are perceived, analyze what we struggle with communicating today at international level, make certain needed distinctions, be more precise while simple/casual. Including alphabet and computer use/communication/programming. There's a lot of extra details AI can account for. Some that we don't even know or understand yet.

I personally think a modern and new global language could help the state of things. Like an actual well thought out subject, with no political abuse at all. Purely science driven.