While you may have issues with certain aspects of TCP and its behavior over WAN, your issues have no practical significance in real life.
Doing a lot of heavy lifting right there. My experience (across many countries, travels, etc) is that internet (and things in general) just barely work to a barely tolerable level. Not a day where a coworker doesn't get some internet issue, some sudden disconnection, some weird TURN route killing latency..
You do not want things running on CPU as that is compute that could be sold to someone else.
This needs an easy way to offload to a specialised hardware accelerator.
Seems AWS is doing just fine with it. They also have built their own custom chipsets though I don't see a mention of it offloading QUIC to those chips.
I think it's fair to call this out, but my initial read, and the reason why I'm responding, is because it seems like you're saying that it's non-viable.