If it’s a good program you are offered, and with your tuition being covered, I would step in and go for the Master’s degree.
You can deepen out and make your portfolio much more specific and you will get the chance to focus on your own development much more than you would in a work environment. And if you are not sure if you want to specialize in a certain area like you mention, this is a chance to dive in there and you may also start to gear your work to such specific areas - which is why the more research-driven companies often ask for a master’s degree. Obtaining my Master’s degree was definitely worth the investment even though I could have started working after the BA as well.