No we aren’t robots in heaven. Is Christ a robot in Heaven? The angels could make a choice, and a third of them made the wrong one.
Besides in heaven, you forget that we will be redeemed into a perfect, glorified state, to a place and creator we want to be with. We will not want to leave. We will experience what Paul and John experienced and not ever want to be away from it. And this was their view while they were still in their sinner/saint status.
God wanted people that would love Him. If anyone knows what real love is it is god, who IS love. He knows what is necessary for the love to be real and genuine.
Real love is made by a person with a free will, that is totally able to make a choice NOT to love back.
For genuine love the ability to not love back must be a real option. Hence the ability to make a sinful decision must exist.
But you point out that in heaven, there will be all those things plus free will. Instead, God has decided to allow torment.
But, I know, I know...I'm just Job, not God, so I couldn't possibly understand. (But, couldn't an omnipotent God be a good enough teacher to allow Job to understand?)