Hi @Ronny Heaven, let's jump right into this!
I'm afraid you can't do this using a shared folder. Do you use a paid plan on your end and if so, which one?
In some cases you should be able to disable downloads if you use shared links, but that depends on the plan you're using.
Keep in mind that if you're using a Basic account, that wouldn't be possible. You can read more about this here.
I hope this helps!