Unfortunately, setting only big goals can feel [overwhelmed / overwhelming] because they often take a lot more time and energy than smaller goals.
Why is 'overwhelmed' wrong? We can feel overwhelmed by big goals and big goals can overwhelm us.
It is the person who sets goals and the person who sets big goals can feel overwhelmed. The only subject in this sentence that can feel is an organism, like a person... so I don't understand why I'm told that if I say "overwhelmed" here the meaning is that it is the goal that is overwhelmed, not the person. That doesn't make any sense. Goals can't feel anything.