What you are really asking is whether you should hedge your US-based investments, anticipating a dramatic fall in the value of the dollar. But even if governments and large corporations start keeping reserves in Euro or other currencies, that doesn't automatically mean the dollar tanks.
You could find a fund that specifically invests in non-US companies. Take note of the fees associated with these, since they will be higher than bog-standard index funds. I wouldn't go nuts and put all your eggs there, though. Take a portion of your overall net worth to bet against America, but don't use it all. It is possible that the global economy decides that the business-friendly Trump policies have enough value to put up with all the chaos, and the dollar might even get stronger.
Always remember as a an investor, you are a small fish, in the same tank as the sharks. You will be shark food eventually. Your goal is to simply survive by not being the slowest fish in the tank.
Someone else in this thread offered Crypto as an option. It certainly seems attractive with the current regulatory environment. But make sure that you understand what you are buying if you go that route. There is a difference between an established currency with its own blockchain and governance, and some random President's shitty token which took no effort to set up and whose market can be tanked by manipulators whenever they want. If you are not interested in the difference, stay far away.