For years my favorite workaround was to dial Singapore reservations, using an internet calling app to avoid high rates. You’d get an English-speaking agent, and the hold times wouldn’t be bad at all most of the time. When U.S. flights were melting down, people call U.S. reservations – not foreign call centers.
Unfortunately you no longer get routed into a separate phone queue by ringing up Singapore. That is no longer a ‘trick’ to avoid the long hold times of the U.S. phone number for Delta.