I have to point out that this "debacle" has been largely positive as it allowed American companies to diversify their supply chains out of China. These tariffs are the reason countries like India are stepping up their manufacturing game, allowing China to monopolize industrial production has been terrible for all countries, not just the USA.
Why would you want to allow one country to withhold all the manufacturing power of our most used devices? That's a recipe for disaster, the whole world was willingly allowing Beijing to become their sole provider of their most used goods because of greed, something had to be done about it.
It's good for the tariffs to continue and for other countries with cheap labor to step up so that the competition for manufacturing is resuscitated, and you can't just simply say "it would've happened anyway" because as far as most politicians are concerned, it was a non-issue to continue to concede to China because they wanted that sweet cheap access to their sweatshops.
Make no mistake, China was hit by the trade war and it's not over, if they want tariffs to be lifted they have to make more concessions in Phase two, and time isn't on their side as other countries will slowly replicate their successful formula, which would be the best case scenario because competition is good.
Not to mention, so far the consumers haven't been negatively affected by these tariffs despite the extreme and the continuous warnings issued by mainstream media outlets. So the longer phase two takes, the more diversified supply chains will become which is better for everyone.
Evidence that China was hurt by the trade war is not evidence that the US benefited. While global diversification would be a fairly small positive, it would not in any way make up for the real damage done to the American economy over the last several years (relative to how the economy could have been in the absence of the trade wars). That said, I struggle to find much evidence that there was actually much in the way of a global diversification.
This piece by the Hindustan Times examines in particular why India hasn't really benefited from the trade war, which largely goes against your assertion. It points out several key facts, including that the US/China trade volume wasn't greatly affected by the trade war. Beyond that, it points out that many countries simply don't have the infrastructure to handle this volume. The trade war is very uncertain. These changes would take years to make and many businesses don't really see the benefit in making a huge long term investment that may not even pay off until after the trade war has ended. A much better option would be to directly diversify by building bridges with diverse manufacturing sectors, not by burning the bridges that are in place.
Further, China wasn't the only country that Trump picked a fight with. Many other areas which may have picked up some of the slack were also targeted by the Trump administration (or threatened, which creates uncertainty and hampers investment). These areas include Canada, Mexico, the EU and...India. Yes, one of the reason that the Trump trade war didn't heavily benefit India is because Trump was also picking a fight with India.
And again, even if this diversification occurred, it would not negate the negative impacts of the trade war. Billions of dollars were spent on a bailout for farmers, with many losing significant portions of their crop due to the inability to sell, prices increased for consumers, American companies had to eat a lot of the costs, business investment has been severely hampered and US manufacturing was in a recession in 2019, with large manufactures blaming the trade war and these issues will continue to be a problem as long as these tariffs remain in place.
The strategy seems like it was far too scattershot. Positive effects were nullified by what seemed like a complete absence of any strategy or cooperation between countries...