hey, ive plotted lets say two variables x and y and used a linear regression model to show the relationship, the R^2 is 0.6 indicating an average fit not strong

the residual graph plotted however shows the linear model is appropriate.
now, by looking at my scatter graph i can see dispersal of y values for larger x values. if i used a piecewise function would i be contridicting my conclusion from the residuals?