I've found that my ability in consistently sticking to a schedule heavily depends on how busy I am that term, with busier obviously being better. This is much easier on work terms since I'm forced to develop strict times for waking up/breakfast/lunch/dinner/etc.

Like this work term it's wake up at 8:30, work from 9-5, dinner from 5:30-7, nap/computer until 8:30, gym from 8:30-10, dinner #2 from 10-11, sleep at around 12. There have only been like 2-3 days out of this entire term where I didn't follow that schedule cause I was sick but other than that I've kept to this routine and it's really kept me in check. Meal prep helps with that a lot too, try to set out an hour or two every weekend to prepare the harder-to-prepare meals in bulk. Easier meals you can just make on the fly in minutes but stuff like making chicken will rack up a lot of time if you're doing that every single night.

During school terms it's harder to keep a schedule due to sporadic things coming up like events/cramming/going out w friends etc. Choosing when your classes are during the day can help a lot with 1) making sure you wake up at a consistent time every day and 2) being efficient in what you do during awkward breaks in between classes (so you're studying etc. instead of just sitting around). I find that the earlier I wake up, the more things I'll be able to do (and I have a bigger appetite so I can fit in an extra meal)