I will provide my perspective as a Canadian regarding currency risks when investing in foreign equities. We have access to hedged and unhedged index etfs here that track ~s&p but are traded in $CAD, for example, VUS and VUN. In case it wasn't clear, when you buy an unhedged index etf, you are taking the currency risk.
Most people would say just get the unhedged version and forget about it since currency hedging is not perfect and the mer can be slightly higher than the unhedged versions in many cases.
It is my observation that over long periods of time, ie, 20+ years, the total returns of the two had been roughly the same. It makes sense, after all, as strong home currency (in this case USD) typically has negative effects on the international portion of the earnings. Granted, neither VUS nor VUN had been around for 20 years, I made my observation using a patched-up VUN by stitching s&P returns with exchange rate differences.
In shorter time frames, either one could vastly outperform the other. VUN outperformed VUS by sizeable margin between 2013-2015 due to a weakening CAD, only to get completely trounced in 2017.
One could potentially make money by jumping back and forth of hedged and unhedged versions of index etfs but I don't see it being viable for most people. My personal record on this has been spotty.