Chosen Solution
The replacement screen I received is much to warm in color when compared to my original. I have 2 other iPhone 6’s they both are bluer in tone.
Is your Night Shift activated" Go to Settings/Display & Brightness/Nigh Shift to check. That function is used to remove the blueish tint from the backlight for people who like to read their devices at night (the blue light affects the sleep cycle). It is possible it is activated. Otherwise, you may just have a poor quality replacement screen. Contact your supplier about a return or refund.