Drying takes place before printing. BambuLab recommends this. I have just dried PAHT-CF myself in a convection oven. However, at a slightly lower temperature and only for 7 hours. I wrapped it up again with desiccant and stored it in the living area.
When the filament is dry, you don’t have to keep re-drying it if you use it quickly enough. It should last two or three days in the AMS without absorbing too much moisture. However, you must also keep the AMS closed. When it is used up, it is good. If the printing results worse, you will need to re-dry.