TPE is well capable of handling ops during a typhoon. I was flying CAN-TPE during Typhoon Usagi last September, and experienced similar anxieties because it was right in my flight path. Most flights (I flew BR) ended up operating and operated on time, because the worst-affected areas of typhoons (and hurricanes) tend to be very localized, and Usagi turned out not directly affecting CAN and TPE.

Unfortunately, it's impossible to predict how the next storm will behave until it actually arrives. For a long flight like SFO-TPE, imo it's the right decision to send it and monitor the situation while on its way. There's no way to tell right now if TPE will be impacted at all.