Hi! Yes, you can add bullet list to the widgets. Select the text box in the widget where the bullet list needs to be added, then in the ‘Visual properties’ under ‘Appearance’ select ‘Bullets and numbering.’ 

From your terminology I suspect you are using version 12. There are a lot of limitations for texts, for sure in the design options of the widgets, you’ll need to live with them. They are even less customisable than the blocks with text components. Which exact widget are you talking about? Is it acceptable to replace the text with a to image converted component?