Help! My daughter's routine has gone seriously wonky over the last couple of weeks.... Is there a developmental leap or something around 10/11 weeks? Or is this the 12 week growth spurt hitting early?!

To date little one has been a great sleeper

She can mostly settle herself, sometimes with the help of a dummy, and has been sleeping for around 9/10 hours at night. She occasionally has one night feed (she's bottle fed) and goes straight back down. Napwise, she's been taking 1-2 hour naps, mostly in her Moses basket, and seemed able to re-settle herself between sleep cycles. In short, much better than her brother who was the catnap King and basically napped on my lap several times a day until he was nearly 18 months old!

We've tried to follow EASY with her since day one, although it's been a bit loose with her brother's needs to consider too! Her routine was looking like this:
W/up: 6.30
E: on waking
A: 1 hour 15 mins
S: 7.45 (for 1.5-2 hours)
E: 10ish
A: 1 hour 45 mins
S: 11.45 (for 1 hour)
E: 1ish
A: 2 hours
S: 3ish (for 50 mins)
E: 4ish
A: 1-2 hours
S: between 5&6 (catnap 30/40 mins)
E: 7ish
A: between 2-3 hours depending on timing of catnap (this was a bit long and she often got cranky whilst we were trying to deal with bedtime carnage times two!!)
S: 8.30 (for 9-10 hours, occasionally with a feed at 2.30/3am)
But for the last couple of weeks she's been all over the place! She started resisting her first morning nap, taking longer and longer to fall asleep, despite yawning and appearing sleepy

She would then be up for 2 hours or more before finally zonking out for a couple of hours and sleeping through her next feed time. Or would refuse to nap/take a 40 min nap and be cranky all day until succumbing to a long nap later in the afternoon (usually in her car seat after a desperation drive!)
I'm not sure what her A times should look like? Her brother has low sleep needs so I worry that I'm letting her go too long by default! (He's three so I've also forgotten what the early weeks looked like!) I've tried to follow her sleep cues and that's been great so far, but now doesn't seem to work... I sometimes feel like I'm trying to put her to sleep when she's hungry and trying to feed her when she's exhausted

She seems to be getting overtired, but I'm not sure how to break the cycle

This is today so far:
W/up: 6.15 (after 9 hours 45 mins)
E: 6.30
S: first attempt 7.15 as yawning, but wouldn't settle. Gave dummy a couple of times and rest of 7oz bottle. Finally fell asleep at 8.15, but only for 45 mins. Tried to resettle with dummy, but got her up at 9.20
E: 9.30 (5oz)
S: fell asleep on bottle at 10.30 and transferred to bed. Slept for 30 mins, wouldn't resettle with dummy or patting. Up at 11.20.
E: 11.45 (7oz - a bit early, but seemed hungry)
S: seemed sleepy at 12.45 so took her up to bed. Down ok after feeding/ dummy, but woke after 10-15 minutes. Seemed to want sleep, but wouldn't settle. Got her up at 1.15 and sat her in bouncy chair while I ate lunch!
S: Started fussing at 1.45ish and got very irate and difficult to calm. I offered her dummy and milk, but she didn't want either. Was considering going for a walk or drive, but she suddenly zonked out on my lap at 2.20! Woke at 3.10 after 40 mins
E: 3.15 (only took 2oz)
S: 4pm - now dozing on my lap again!!
Does anyone have any suggestions? I'm so desperate to get her back to napping in her bed

I really need that time to spend with her brother on non-nursery days, plus the thought of her needing to be held/driven/pushed/patted for every nap like he did is making me feel so anxious

I should add that she suffers from reflux so feeds can take a long time..... she tends to eat throughout her A time, little and often with plenty of wind and posset in between! It's sometimes tricky to separate feeding and sleeping because of this, but I don't think there's a major sleep association being created - she used to stop feeding, burp and then go down quite happily. However, she does often spit up everywhere and need a change of clothes, bedding etc. This then means resettling afterwards and can add to her overall A time

Any thoughts or suggestions very welcome! xx