13.5wk - sleep hygiene and prep work?

We have about a week’s worth now of sleep logged for our 13.5 week old.

Total avg daily sleep is 12 hours
Daytime naps total 4.5 hours
Night time sleep starting around 9pm totals around 7.5 hours

Sounds like based on this she is right on the lower end of “average” sleep needs?

If her sleep needs stay like this, how do we go about shifting some of the daytime naps to be for night time? We currently do daytime naps based on her cues so the actual timing and wake windows are not very consistent. Though as the app states, it all ends up being around 4.5 hours each day so at least that stays consistent? I’d say we avg around 5-6 naps each day.

If we wanted her to eventually have 10 hours for night sleep when we start ST at 4 months, is it as linear as taking away 2.5 hours from the 4.5 daytime avg and sticking to capping at 2 hours of daytime naps in order to get the 10 at night?

Sounds like we’ve gotten her used to a 9ish PM start for the night, which is ideal for us if we were to want to aim from 9pm - 7am when all is said and done for her training. Is this a good start to this? Would love to hear any insights or experience from anyone that’s also been aiming to (and/or successfully) done a 9pm-7am schedule. Heck, even 9pm-8am (though I know that’s harder based on a lot of infants naturally waking around 6am/7am)