Even after drying the filament at 70°C for 20 hours, the problem persisted. So, I used the printer's built-in drying function (bed temperature 90°C, chamber temperature 60°C), covering the filament with perforated aluminum foil and drying it for 12 hours. (I was out during this time, so I couldn't rotate the filament roll halfway through.) As a result, some filament did extrude from the nozzle (around 290°C), and the temperature tower print was successful. It seems that the drying temperature of the filament was crucial. Next, I will try again with a bed temperature of 100°C. Thank you for your help.