After having seen the different performances among some US and EU indices, let's see it on a chart and briefly introduce a very important concept in trading: spread (or pairs) trading.
It's something that few retail traders use, preferring to go outright (taking a risk directional position); at the opposite, it's very uncommon that institutionals will work without having somehow covered their risk with a spread.
What you need to do is to find 2 securities that have some common characteristics (geographical area, sector, etc) and can show a somehow correlated trend in the long term. Ok, properly they should show co-integration, but let's keep statistics out of this for our purpose. Then you go long one and short the other, playing the spread.
Here you have a chart of the difference in the performance between SP500 and DAX, first one daily since the end of 2017, and second one on a 2h timeframe since Aug 2019.
I'm leaving up to you to think about it and which strategy you could imagine going forward.