It’s hard for me to tell what’s going on in the pictures but it seems fine, at least to my eyes. There’s a possibility that the replacement screen was defective or on some devices, if you don’t disconnect the battery while replacing the screens, you can blow the backlight or image circuits. You’ve done enough diagnostic alone to determine that the device works and it should actually in fact, be worth fixing. You’ll want to have a skilled micro soldering tech perform this repair as an inexperienced tech can cause more damage and really mess the device up. I highly recommend either iPad Rehab, Rossmann Repair, STS Telecom, or VCC Board Repairs. They all have youtube channels you can check out and they’re very knowledgeable. I’ve personally been to iPad Rehab for their board repair school and I’ve personally used VCC Board Repairs for repairs I can’t handle in my own repair shop. But before you send the device off to either of them, at least try one more screen just to be safe.