@Ashish…
There is no soul as such, meaning soul as a specific/permanent-self-with-a-beginning in Buddha Dhamma. What exists is a mental body (gandhaba as you mentioned) resulting from endless rebirths… unless nibanna.
Another interesting definition that is given here to the whole formed by the gandhabba + body of flesh (as for human bhavas…) is “lifestream”, but one that goes on changing as per one’s intentions, thoughts, speech and actions.
This lifestream will go on endlessly unless it comes across a Buddha.
I’ve no interest in to consider myself a teacher here, so don’t consider this a teaching, it’s but my view on your subject – as allowed by the forum rules.
:-) !!