Topic name is self explanatory. There’s no way to pause music (or anything) playing with Time Synth. It was possible in 4.22 by deactivating TimeSynth component and re-Activating it. But since version 4.23 it doesn’t resume playback of previously loaded clip if new “audiomixer” is enabled. Same in 4.24 which has new audio mixer enabled by default.
Seems like a basic feature. Very much needed for any music driven games/applications/experiences developed in Unreal Engine.