Newby Help - Wind reacting on a balloon

I am struggling with a scene where I want to have alot of balloons floating into the air. Phase one is to get control of one balloon but I can’t get the baloon to react quickly enough. If I try with a cube, I manage to get reasonable results quite easily, but a balloon seems to be very different in my scene.
Phase 2 is to work out a way to have hundreds of baloon that fly off into the distance, therefore to find a way to optimise the scene.
I attach the scene so it is clearer. If anyone can explain why it is not working I would be very grateful.

There is nothing attached to this post. But one question: do you want to have strings on the ballons? hundreds of balloons without strings floating around in the wind is really simple, with strings attached ,that need to bend in the wind, is slightly more complex.

Thank you for the reply.
There some to be a lmit on file upload size, so I have added a test file.
You have guessed it. The balloon has string and eventually a little card. Why is the string so difficult?
Thanks again.