How’d they get into my truck..?

2019 ram 1500 classic

Parked at my girlfriend’s apartment

I’m very vigilant about locking my doors

To the extent, it would be like someone happened to prowl on the one night I’ve ever left my doors unlocked

So, seeing as there was no “forced entry” were they able to clone the fob somehow?

If so, is there a defensive measure I can take to prevent it, aside from covering the vin?