A kettlebell swing should not be a squat. If the kettlebell travels below the knees during the exercise then you're squatting your kettlebell swing and putting too much pressure on the lower back instead of using the glutes.
To correct this, stay upright a lot longer than you think before you start hinging (or bending) at the hips. One way to get yourself to hinge back is to imagine the movement you'd make if you were kicked in the junk. Your hips are going to hinge back violently – you're not going to do a squat.
If you've been around weight training for any length of time, you've probably read or tried an arm specialization routine. There are a bunch of these around with different cool names for what amounts to the same old shit: do a bunch of arm exercises. Yeah, the exercises change and the sets and reps change, but it still amounts to just doing more arm work.
Whether you're taking a planned break from training or you're struck by sickness or injury, there are plenty of things you can do to prevent muscle loss.