You could bypass the need for timelines altogether by doing “Time - TimeOfStep” inside of the material.
That way all you need to do is set “Time of Step” on the initial creation and then the fade can be calculated from the material itself. You would multiply/clamp to get that into a 0-1 range. In this way you can cheaply time fade a bunch of materials without paying the cost of ticking them all.
To get time matching the time in the material editor you need to use “get real time in in seconds”.