Add a new trace or trendline to frames in an animated plot

Is there a way to add a new trace or trendline to only one frame in an animated plot? I would like to add my own trendline or trace to each frame in an animated plot.

fig.add_trace(go.Scatter(x=[4.5, 5, 7], y=[3, 4, 6]))

This will add the trace to all frames in a animated plot. Furthermore, I would like to add multiple trendlines to sections of data within one animation frame e.g. a piecewise trendline. How would this be done with plotly or plotly express?