mute/unmute selected tracks

Is there any way to mute/unmute selected tracks?

Not based on track selection

But yes, use the Mute button on the track’s Track Control Panel - see:

You could temporarily “mute” selected tracks by turning them to silence with Ctrl+L - and then restore them with Undo - but you wouldn’t want to do anything else in-between as Undo is not selective, it woks backward through each command one at a time.