My advice is you’re already taking some good academic subjects so for your last option pick the one you’ll enjoy the most and will give you least stress.
If you find Latin quite easy then that’s a good option because less stress the better. But then consider that if you find it super boring you won’t want to revise and this will increase stress.
Art and D.T do often have big projects that take up time. In my GCSEs I took D.T as my ‘fun’ subject but it was actually a cause of big stress because I was always staying behind after school to catch up coursework. Having my time again I would have taken P.E.
Overall my advice would be think which you’ll enjoy and find least effort and pick that.
One way to decide might be roll a dice, (1-2) Latin, (3-4) art, (5-6) German. You may find yourself hoping it lands on a particular one and that will tell you what you really want so then you can pick that.