Unpredictable baby?

BlissfullySweet • Married to my awesome husband 💑👫 Mommy to my precious boy 💙😘👦🏻and 2 sweet girls 💜💜😘😘🧒🏻👶🏻. Baby #4 (the finale) due August 2021. 👶🏻💙🙏🏼
Am I the only one whose baby is unpredictable at night? I read moms who post their babies bedtime and it sounds so concrete explaining how their baby sleeps from this time to this time every night. My son is not like this. Every time he sleeps at 9pm...I never really know when he'll wake up. Two nights ago he slept from 9pm-7am. *cue hallelujah music* Yesterday 9pm-5am, ate, and went back to sleep till 9am. Tonight...he slept 9pm-midnight, ate, went back to sleep and woke up at 3:50am, ate, and is currently still awake at 5am... I just don't get it. WHY can't he be more regiment in his sleep?! 😩