@Iconic_lettuce Hey, welcome. Hmm that is weird indeed. Usually when this happens it’s mostly a problem with either the tablet’s drivers being oldish or the operating system being annoying.
If you’re using Windows 10 please try looking into this guide: Pencil2d automatically creates straight line when i put my drawing pencil on it
Even if you’re not using a Wacom, try mirroring the advice to your own device and drivers. Particularly the “windows ink” part and follo the windows “compatibility” guide linked there as well.
If you’re using a macOS or linuxOS machine, let us know as there might be something else we can recommend.