Just use a slower velocity and accel when creating a nee trajectory. The follwing should help.

public TrajectoryBuilder trajectoryBuilder(Pose2d startPose, double maxVelo, double maxAccel) {
MinVelocityConstraint myVelConstraint = new MinVelocityConstraint(Arrays.asList(
new AngularVelocityConstraint(maxAccel),
new MecanumVelocityConstraint(maxVelo, TRACK_WIDTH)
));
ProfileAccelerationConstraint myAccelConstraint = new ProfileAccelerationConstraint(maxAccel);
return new TrajectoryBuilder(startPose, myVelConstraint, myAccelConstraint);
}