@welzey Hi. Once you’ve answered what Ralmon has kindly asked, can you also please confirm what is the brand and model of your pen tablet? Also please state your current Operating System as well.
After that just to make sure to preemptively check that your drivers are up to date (2022) and your tablet preferences / options panel are configured with adequate pressure sensitivity options.
Additionally if you’re using Windows 10 it is absolutely necessary to configure the Windows Ink feature in order to properly use a graphics tablet from any brand.
Below I’ll leave a Guide on how to configure windows ink where Wacom hardware is used as an example, but this should work for any brand and model since it’s a Windows configuration procedure.
Once all of that is done, please check in the Pencil2D Editor that the stabilizer function of your every drawing tool is set to None and not Strong nor Simple This feature is an input noise filter that has been found in very rare cases to enhance input signal jitter on some pen tablet models, particularly those that have been refurbished (including the Wacom One or CTL models).
Changing the setting should reduce common issues related to squiggly lines or involuntary blotches.
If you still can’t get it to work properly, let us know so we can consider other alternatives or suggestions.