Hola Manuel, thanks for the feedback!
We are working on a new type of text object. With that it will be very easy to customize text, change the font size and the size of the text field itself. It should be coming in one of our next updates and I’m going to come back to you then.
At the moment it’s not possible to change the font size and the size of the speech/think bubbles but I’m going to forward your request to the team.