iPhone 6 with backlight no image

Hi, I'm trying to repair my iphone 6. Recently I decided to fix my old iphone and resell it, I opened it I could smell the chemicals from the battery I removed carefully and yep the battery was pierced but surprisingly still working I removed it and kinda forgot abt the whole thing. When I finally ordered a new screen and a new battery and turned it on i just got the backlight on, I triple checked the connectors and brushed gently to clean them but still just the backlight. Since I'm no expert in microsoldering I went to my local repair store and asked them if they could check it. Abt a week later I go and they made a diagnosis this were his exacts words “yeah is a screen problem” so it just needs a screen replacement “no, it's a cable problem” oh so it needs new flex cables “no it has” which at that point I don't even remember what he said but is sounded like complete bs. I'm kinda broke and need this phone to work can someone help me out fixing this phone? Thank in advance! (sorry for misspelled words I'm half asleep)