Really struggling with my toddler daughter

I swear I have the hardest to deal child ever to exist. She wakes up at a decent time and goes to bed at a decent time I would say her sleep has been very broken and lately hasn’t been able to settle properly until about 2am in the morning. Between 9pm - 2am she’s in and out of sleep and when she’s up she’s crying and throwing fits. I wake up at 6am every morning to go to work leaving me with only 4 hours of night sleep. I suffer from severe fatigue affecting my day to day and how I perform. I try and keep my cool and stay patient but I yell at her a lot she gives me such a hard time everyday. A big part of why I’m so snappy is clearly because of the lack of sleep I’m getting at the moment due to her regular night time wake ups. We both need the sleep I just don’t understand why she’s not settling. She’s always dressed accordingly to the room temp, I’m always making sure she’s fed well before bedtime, water is always by bedside, she gets lots of cuddles and reassurance from daddy. I just don’t understand why she’s waking up so often and STAYING awake being such a nightmare. I had to go and sleep in a separate room last night because she’s just a lot at the moment and she overwhelms me.