How do you repeat multiple times in MuseScore?
This works fine in terms of getting MuseScore to play the repeat (I set start and end repeat bar lines, then right-click on the last bar, select Measure properties from the context menu and set "repeat count" to 3).
How do I change the number of repeats in MuseScore?
If you want to change the number of times MuseScore plays a repeat, go to the measure containing the end repeat barline and change its "Play count". See Measure operations: Other properties and the note on playback for voltas in Repeats and jumps.