Except the Constitution doesn’t say we must declare war. It says “OR in adhering to their Enemies, giving them Aid and Comfort”. The case could be made that China is indeed our enemy and he certainly has provided them aid and comfort and, at our expense.
I take the text actually as I see it. If you have to make a case, you’re interpreting the text. I leave the finding of “penumbras & emanations” in the text to leftists like Justice William O. Douglas! I think it’s the wrong thing to do. You end up twisting the Constitution into what you want it to say, not what it says! Also, in examining the following link you will see that:
https://en.wikipedia.org/wiki/List_of_people_convicted_of_treason
All treason cases were in either active wars or rebellions - even rebellions like the Whiskey Rebellion. The exception is possibly the Aaron Burr case. Not really much of a rebellion but certainly against US interests. In that case Justice Marshall set the treason bar even higher. Burr was acquitted.
Note Dore’s and Browns treasons were against their respective states NOT the USG. I don’t know if such a charge of state treason could be made today. I imagine most states don’t even have it their state constitutions today. If the states are sovereign such a thing, should still exist!