But there are times, when for no apparent reason, she just decides to destroy parts of the garden.
Does she attack plants?

Or is she mainly going for the places with freshly dug dirt?
My cats would dig up seedlings too, if I didn't take steps. They're not being malicious, it's the dirt. (It's the dirt!

The diiiirrt!!) Once plants are about 4-5" high, they'll leave the dirt alone.

I wouldn't know what to do with a plant attacking cat!
This is what I've learned from having too many cats.
If you want to grow outside from seed or transplanted seedlings,
you have to .cover them or build a barrier. You could use a milk crate or an upside-down old laundry basket. (You might want to cut holes in it to let in more light.) I usually try to find things I can recycle.
For the veg garden, I have two old tomato cages that I cut in half, and use the four pieces to make little surrounds for protecting seedlings and new transplants. If the cat were really determined, I'd try to block entry with little sticks, or bamboo skewers, or garden stakes.
I originally tried to use cheap plastic fencing for edging my flower bed.

It does not stand up well to the weed whacker.

So now, I am using rocks along the flower bed, and I have incorporated the fencing to protect my plants.

Next year, there will be a nice little clump of Butterfly weed between the flamingos.
I have never found a smell that repulses my cats. I've had them smell peppermint oil and orange peel. They don't care. I've heard about using hot pepper spices, but if that bothered them, then why did one jump on the stove and steal a Buffalo chicken sandwich?

I won't try mothballs, because they'll repulse me!