@kavalisridhar there is a lot that seems to get lost in translation. Give us more descriptive information about what is going on with your phone.
It is entirely possible that it doesn't come on because of the display issue. I would start by replacing the display. That way you have a known-well part and can do any further troubleshooting after that.
Since iFixit does not yet have a guide for this, use the one [https://www.nadiemellamagallina.com/en/manuales/smartphones-1/vivo-926/vivo-y35-4g-1452/pantalla-completa-13286|from here] Replacement displays are readily available at many online stores.
While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.