4 mo able to link sleep cycles 3 days out of week, will cio help,?

Our baby just turned months a couple of weeks ago and we've had nights where baby is able to do 7pm to 2.30am with maybe one or two whimpers here and there and the occasional shush to go back to sleep.

Does CIO help in this scenario or is just pain being inflicted with no real gain?

I hear that CIO is really useful when baby is utterly incapable of linking ANY sleep cycle and wakes up every sleep cycle.

First of all are there babies that get up every sleep cycle?! Like truly the case not us parents miscalculating.

Then if yes or no to whom is CIO most useful?

I am dad a night owl and have no problems servicing baby till 3am after that it's sort of light sleep anyway and Mom is the only person able to handle the every hour to wake up from 3am till 6am.

Again I've inadvertently done CIO one night where we couldn't immediately attend to baby for 15 mins and it was unpleasant because baby went into distress crying which is painful to hear but the baby did ultimately sleep.

All that to say I'm not opposed to CIO or rather maybe Fuss It Out but I'd like to understand the returns I'll be getting.

What gives me real panic anxiety is baby being up for 2 hours in the middle of night. That happened last night and I'm reeling.

I'm ok with multiple wake ups for me but again I hate it for baby but I'm told split nights is considered significantly worse than say multiple wake ups.