Even if you make a good trade and your hedge protects you from a downturn, you've "broken the seal" on trading. Amateur traders almost always lose money in the long run, and once you make a bunch of money on your first trade it's hard to stop. Like the curse of beginners luck on slot machines.
But that said, I don't think (again, sort of definitionally) there is a "best strategic hedge" in the face of a trade war. In trade wars everyone loses. You can't meaningfully bet against a shrinkage of the global economy in aggregate.
Well there are many ways to default, and many shades of default.
I can very well see the current administration argue that China, for whatever reason, owes the US, and thus should be compensated by confiscating bonds.
Personally, I view my market investments as already fixed. I'd like a non-correlated asset, which means I'm looking at real estate. In my case, this goal isn't growth, inasmuch as defensive capital, or forced savings. I have the exposures you do, but added several, multi currency risks.
I guess the answer is to diversify away from the USA trade? But then to what?
If does not sound like you are an active investor?
For "paper assets" I apply, and would recommend, lifetime investment in a global, well diversified portfolio. Ie. I adjust my risk tolerance with leverage and not by picking positions. There is no reason why commodities, metals, crypto should not be a part of your "paper asset" portfolio. (I call it paper assets as "stocks" seems to mean ownership in companies, which is a bit too narrow - there are ETFs for most of this stuff)
Housing is a personal question. As an investment it usually does not pay off and compares to stock picking / active trading.
... Did they? Which countries? What made you think that?
S&P500 is down about 9% YTD. FTSE250 (UK) down about 8% (but that's in pounds, and the pound is up 5% on the dollar). Shanghai Composite Index(China) is down 2.5%. Stoxx 600 (Eurozone, broadly) is down 1.5% YTD. The only big one where what you say _appears_ to be the case is the Nikkei 225 (Japan), which is down 15%... but remember that it's denominated in yen, and the dollar's down over 8% vs yen in the same time.
As far as I can see, the only way you could even pretend this was the case would be by ignoring the decline of the dollar, and even _if_ you ignore the decline of the dollar that only really works for Japan, not Europe or China.