You're not necessarily doing anything wrong at all
The 3-4 month window is a time of big change for babies because their sleep stops being like a sleepy newborn and starts taking on a more mature sleep cycle pattern. It is often a time when apparently independent sleepers appear to regress (you may have heard of the four month sleep regression), and short naps are very common as LO needs to learn to transition between sleep cycles without fully waking. There is also a big growth spurt at four months or thereabouts and it is normal for a LO to start waking for an extra feed when previously they didn't need one, or to fuss more for feeds in the day.
Often newborns will just drift off to sleep on their own. That doesn't seem to be quite the same thing as true independent sleep from what I've seen and read here, it's more like they just 'pass out'. But when they notice there is a world around them they start needing a bit more help and guidance towards switching off and falling asleep alone. Do you have a winddown routine? Do you use a paci/swaddle/blackouts?
With the EASY you posted I'm not quite sure when you really started your day? Her first A time 6.15-6.45 is so short I think probably that's really a night waking, and her real day seemed to start at 8.45am. At her age you'd expect a typical A time somewhere in the range 1h30-45ish (
Average A times- BOOKMARK ME!!). Hers are a bit variable between 1h and 2h but that can happen. It may be that the long first A time tired her out quite a lot so she could only handle short A times as the day went on.
I would maybe try shh pat in the crib rather than your arms so you don't have the jolt as you lay her down, or maybe start out shh pat in your arms until calm/drowsy but put down before she is properly asleep and finish off in the crib. For the 45 min wakeups you can just leave her if she's happy - she may drift off again after a while without your help. Or you can try resettling with shh pat if she's upset, or getting in there from around 37 mins on and gently pat her through the sleep cycle transition as soon as you see her stirring.
What do you think?