Currently at 12 weeks. When 4mo and beyond, how can I ensure a 9pm to 8am when we start to ST?

So as of right now, we don’t do anything sleep train related to be honest. We go off her cues during the day and thus have pretty inconsistent daytime naps because she has a lot of short naps. Though I will say they probably total about the same hours which sounds like the important part?

Here’s where we currently are for night though. When she goes down around 9:30pm she sleeps until around 1:30am or even (rarely) 2:30am (4-5hrs). From there, we bottle and she goes back to sleep from around 3am to around 5am (2hrs), and then another bottle and then asleep from 5:30am to around 6:30am (1hr).

So to my understanding the 7-8 hours per night is obviously not sustainable as she gets older, but I assume it’s been doable for us since her naps have been totaling longer during the day for her age.

Is there anything we can do to encourage the same-ish 9pm bedtime once she’s ready at around 4mo+ if she’s already kind of associating her bedtime to be there with that first longer stretch currently?

It would really work for our schedule if she was 9pm to 8am. Wanted to see if anyone has a similar schedule and could share their day nap times so that we can get a rough idea of how to space them out as she lessens her total day naps.