Sounds like yours is chattering. Uneven engagement, not smooth. Like the disk is warped or the flywheel or pressure plate aren't flat. Or maybe the smoothness of those surfaces isn't even. That's completely different than slipping.

As the clutch wears out the disk gets thinner. Eventually its so thin that the pressure plate runs out of travel, & can't squeeze it hard against the flywheel. Then it slips.

You can make any clutch slip just so you know what it feels like. Push in the clutch pedal just about to the point where it begins to disengage, then try to accelerate. The engine rpm revs up but the car doesn't accelerate. This isn't the best way to treat your clutch, so don't keep doing it for fun...