If we get into it with China, tubes will be the least of your worries.
There's virtually no consumer product made that doesn't have components made in China within, not to mention vast swaths of the food supply, pharmaceuticals and frankly 99% of all face masks on the market for both the medical field as well as for COVID precautions.
I've only purchased power tubes from New Sensor and they do sound different. For an EL34 amp I've tried EH, Mullard, and Genalex. Their Mullards try to capture the sonics of classic UK tubes (warmth, smooth highs) but don't come close. However, the Genalex GL-77's are excellent, dynamic, open, smooth top-end extension.
Edit: I shouldn't be so critical of the new Mullards. They're fine in some applications where some warmth is needed. But they are Mullard in name only.