Not all indicators are suitable to have an option to be applied to another indicator data via mt5 designed / allowed options. Linear regression line (original that uses "simple" prices posted here : Linear Regression line) is one that is suitable

We have regression channel as objects, but it needs to be constantly adjusted if we want it to follow new bars forming. Hence : here is the version that can be applied to another indicator(s)

PS: examples do not show it, but the color of lines changes depending on the slope of the regression line