My wife and I live in Ecuador so we are using Copa to SFO. The two daily flights from SFO to SIN are completely filling up se we bought Premium Plus and even thought we are first on the list for Points Plus upgrades our only chance will be last minute cancellations in Polaris. We will then fly to Bali on Jetstar (way cheaper than Singapore Airlines) and on to Sydney on Virgin Australia. From Sydney via SFO my wife will be on a mileage ticket with in Polaris and I easily got an upgrade with Plus Points from Economy. To make a long story short, I would suggest when you can start booking for 2025 to Bali try through Australia, not Singapore.