I had the exact same worries as you when my baby started rolling. All you can do is follow the safe sleep guidelines and have her sleep in your room, in her own cot, always put her down on her back and clear the cot of anything.
As others have said you can buy an Owlet, which might give you some peace of mind. I did consider this myself, but read they could give false alarms, which I felt would be quite traumatising.
I would also practice tummy time as much as possible to strengthen her neck, so she learns to roll properly. I felt more relaxed when I knew my baby could move around independently.
When my baby started rolling, I used to constantly put her back onto her back, but it is exhausting, especially if you are on your own. Ultimately the safe sleep guidelines are drilled into us (for good reason) but it’s important to remember that SIDS is rare, and when I was a baby I was constantly put down on my front, as that was the advice at the time.
All you can do is follow the current guidelines, and as she gets older and can move about independently, hopefully you’ll be able to relax.