If you haven't already, clean the dryer vent thoroughly, including the whole exhaust vent leading outside. This should be done at least once a year. Once the vent is clear it should speed up drying, if not it might be the dryer itself and the manual might have solutions.

Here are some guides: https://www.familyhandyman.com/article/how-to-clean-a-dryer-vent/ https://home.howstuffworks.com/home-improvement/home-diy/projects/dryer-vent-cleaning.htm