Taipei is 6 hours ahead of Warsaw
Best overlap: 8:00 AM to 12:00 PM in Warsaw is 2:00 PM to 6:00 PM in Taipei.
For a call that suits both sides, look at 8:00 AM to 12:00 PM in Warsaw / 2:00 PM to 6:00 PM in Taipei. You share roughly 4 hours a day. That's enough for regular meetings, but treat the window as prime time and guard it. Finally, Warsaw observes daylight saving and Taipei doesn't, so this window shifts by an hour for part of the year — recheck it each spring and autumn.