Screen keeps losing colour and ends up with a blue tint
On this model there tend to be two problems. One is that the power supply capacitors fail early and often. While this typically caused no power or slow power-on, it can cause other issues as well.
Loss of color typically means the 'Main Scaler board', which is the main board where all the inputs are attached, is having an issue.
There are some problems reported with a faulty crystal on the board causing loss of color, although most techs would just swap the board as these TVs are meant to be serviced at the board level, not the component level.
I assume that this loss of color happens on any input source, including when using the internal setup menu of the TV? This would help to confirm that the loss of color is not related to a faulty input signal caused by a bad cable.