There is a way within the UI to change the font size for dashboard and component titles. This can be done by navigating to Administration > Profile > Large display mode.Unfortunately, this will not change the font size for the chart itself. There has been an enhancement request made regarding adding this functionality at the link below:
Please be sure to vote on this if this is something you'd like to see us look into adding in future versions of Xtraction. We are always looking for ways to improve the product and the more visibility an enhancement request receives the more likely we are to look into adding it in the near future. Please let me know if you have any questions.