The next tracking update after the initial "origin post is preparing shipment" is when it's processed through customs in the destination country, which can take a while depending how backed up they are (can be a lot during holidays and/or pandemics). Your tracking on 17track probably looks something like this:
There may be a date code in the Chinese language section which tells you the date it was scheduled to leave Taiwan. If it's after that date and you haven't seen any other updates, it's safe to assume it's sitting in customs in the destination country waiting to be processed.
You shouldn't rely only on 17track for tracking, especially for countries outside the US. Tracking through the local courier's website will provide more information on how to pay import fees (not required for the US) or to arrange delivery.