There are a number of reasons for Kodi buffering. #1 is probably the most important.
1. Having a good internet connection. How fast is your connection? (Use an app like speedtest). Wherever possible use an Ethernet connection over wifi
2. What droidbox model do you have? Models like the t8 series have more powerful processors.
3. Do all Addons buffer or just some? One of the main causes of buffering is too many users hitting particular streaming sources . Think of it as a traffic jam. All you can do in these cases is find a different source.
4. Do regular maintenance on your machine. Clear cache regularly. The ares wizard has a good tool for this.
5. Wherever possible, reduce the number of Addons you are running. Wizards notoriously load tens of Addons you never use or are out of date. The more you have, the more likely performance will be affected.