Or just write your own custom frame synchronizer. It's pretty simple, actually. Refer to the frameAlign example for inspiration: https://zorro-trader.com/manual/en/tips.htm
Given enough time, I can write my own custom backtester. Do you mean to say that asking for frameSync() to work in some practically useful timezone is suuuch a narrow use-case/special request that it is to be left to be programmed by the user??