@FeedMeBrunch sorry for the delay in replying. I've read your other posts, too. You do have to feed on demand and not try to schedule feeds. They are very good at knowing when full. What you can try to do is to burp baby and offer bottle after that again to see if it was just gas. It usually isn't much more complicated.
I combi fed my first (now 3) and pretty much ebf my second (now 12 mos). It def is a pain dealing with bottles, sterilizing, flash cooling, etc.
For each day: You can make several servings of formula in a sterilized mason jar and keep in the fridge. Then sterilize several bottles/nipples and seal in a ziplock bag to use as needed. I would then boil the kettle and pour boiling water into a bowl then put bottle of formula into that for a minute, test, put back in if needed, test again.
Feeding is hard for the first while. It's frequent. We're tired. Hormones. Anxiety. Worry if we're doing things/right or wrong. We read about nipple confusion, breast is best, do this/not that, reflux, tongue tie, baby is allergic to bm/formula etc and often nothing is wrong but we get convinced something is wrong. Babies feed on a schedule, then they don't, then it's cluster feeding, then they change again. The main things are nappy, tired, discomfort (gas/hot/cold) and sleep. And I found with mine that holding them a lot meant they rarely fuss/fussed.