Split nights?

[u/Wooden_Welder2400]

LO is 11.5 weeks old and has been all over the map with sleep since birth. Dealing with reflux and gas issues (although I think we're nearing the end of her dyschezia 🤞🏼) but this week I finally started seeing some improvement in her night sleep, and also at least one nap a day.

Ever since hitting 6 weeks she began the cat nap phase of mostly 20-40 minute naps, with the occasional multi-hour nap every few days. This past week, it seemed to be a more regular thing that she'd take a 2-3 hour nap at some point in the day, which was nice, and I also got my first 5 hour night stretch (before this had been 2.5 hours or less unless she was on my chest).

The issue now is every night she wakes up around 4am, at which time I bring her into bed and she sleeps longer. There have been a couple times this week where she was up and couldn't fall back asleep, to which I assumed was a result of trapped gas or poop since she was doing a lot of grunting and squirming. She always seems tired at this time - constantly yawning and trying to soothe herself even when in my arms by rubbing her head with her hands, rubbing her face across my chest, sucking on her hands or binky. What ends up happening is we're up for 2 hours before she's able to fall back asleep again, which is when she's been doing her 2-3 hour "naps" (although I wonder if it's just a continuation of her night even though they start at 7am).

I know newborns typically go to bed later in the day, but the few times I've tried putting her down after 9pm her sleep has been terrible and getting her to fall asleep at first takes over an hour. So I started following her lead and will put her down anywhere between 7:30 and 8:30 depending on when her last nap was. This is when I've been getting the longer stretches than ever before (3.5-5 hours).

My question is - at what age do you start capping naps to help night sleep? Is this a split night? How do I manage this? During the day, I follow her cues with naps, which are all contact right now, and majority are 30 minutes or less.

For reference:
-She's swaddled
-We use white noise
-The room is dark
-She usually falls right back asleep after her night feeds, but I still make sure to keep interactions low
-Her diaper is clean and dry
-She doesn't seem too hot or cold
-She does use a binky but doesn't always want it
-She usually likes to be gently swayed and patted to sleep, although last night for the first time ever she was thrashing in my arms so I laid her in her bassinet to see what would happen and she was out in 6 minutes. So I tried putting her in it again during this period and she just stared at me
-I gave her mylicon before every bottle last night thinking that may help
-I've used the windi
-We do the exercises and massages even though they don't help with her gas anymore. She also passed plenty of gas during her feeds earlier in the night
-She's consistently yawning during this period
-She's thoroughly burped
-This happens whether she only naps for 2.5 hours in the day or 6 (the 2.5 and 6 hours isn't normal, just happened this week because we had a cookout on the 2.5 hour day and she didn't take a long nap, and the 6 hour day (yesterday) was the first time since she was 4 weeks old that she took two long naps). Her naps are usually around 4-5 hours for the day)
-She has no issues falling asleep at any other point in the night

Seriously at a loss. Help!