Hiya.
You may have more than one issue.
The alarm can be triggered by any air movement inside the car, so ventilation could be an issue, i.e. don't park it with anything left open.
(Or if you do, use the button inside to put that alarm into 'pet mode' to stop monitoring internal air movement.)
Small animals could also trigger it, so probably worth searching the car carefully for any sign of an uninvited guest.
Phantom unlocking is a different kettle of fish.
My first thought is to check where and how you're storing the key fob.
If it is just staying in your pocket, there's a chance that it is 'pocket dialing' i.e. the buttons being pushed by folds in the fabric of your clothes etc.
If you share your home, or have regular visitors, I'd be careful of them having access to your key fobs. The internet is full of 'friends' playing tricks on people.
In my case, I was sure that my car was unlocking by itself, but when I decided to make a routine of checking the car before I left it, by lifting the door handle and then manually folding the driver's side mirror to show that I'd checked the lock, the mysterious 'unlocking' stopped.
So in my case, I'm pretty sure it was me, not locking the car or worse, locking it, then unlocking it again by using the tailgate.