Thank you for giving your opinion. That is what I thought and will try this way to optimize the collections and products and hope that I would at least get some transactional traffic.
Although, It would be really tough to manage all the keywords for a single collection. For example, in the Floral T-shirts collection, Support if we have 500+ products under it then managing the keyword will be a tough job, but yes I will try this way to optimize my store now.