Define excessive discharge. In-battery circuit kicks in at 6-8A. Battery is specced for max 1.4A continuous charge/discharge current. With the safety margins in these things, it will probably take 2-3A continuously, too. But can it take 4A for 1 hour? Wanna try?

Also, there's no protection against excessive temperature in the battery protection circuit's specification, so not sure where you're taking your information from. It would be nice if people actually used the datasheets that are freely available, since Pinephone is mostly open HW, instead of proclaiming random generalities.