Honestly I think if you felt there could be a reflux problem this could be the issue.
My DS was suffering silent reflux for several months before he was diagnosed and in that time various health visitors and GPs said he was fine, a "happy spitter" they said ("he's NOT happy he's just polite to strangers" was what I said). We saw so many docs. Every time I was told he was fine because he was consistently gaining weight and thriving. he was not fine. They didn't see the screaming. Eventually I put my foot down and demanded a referral to the paediatrician at the hospital and also bought some over the counter reflux meds on agreement of the pharmacist (infant gaviscon which really only helps short term).
When we finally saw the paedi (DS was 5.5 months by then) she diagnosed silent reflux within 2 mins of entering her office and gave me a prescription for proper reflux medication. And within a couple of weeks or less he had calmed down.
Coincidentally the "4 month regression" ended at 5.5 months too and he started taking proper long naps just as he had when he was younger before the reflux got so bad.
I am also a first time mum, I only have one child. I've been through a lot of "Oh he's your first is he?" every time I take him to the doctor, to be honest I am fed up of it. There have been several medical issues I have resolved by pushing hard for attention rather than being given the "he's your first" response. We may well not be highly experienced as first time mums but we can and do have an instinct and we spend a lot of time with our babies to see how they are effected.
Personally I would push for a referral.
The better sleep your LO gets with others could also be more of a "they can't solve my pain so I will not bother to tell them how bad it is" whilst with you she her approach is "this hurts, I need attention". I know this might sound a bit out-there but it is amazing what our babies tell us that they don't tell other people, it's just that everything they say is crying because they haven't learnt to talk yet.
I'm guessing of course, I'm not a medical professional and I am only hearing what you have described. There can be long lasting problems associated with untreated reflux.
Here is a link to our CRC (colic reflux and crying) board, there are a couple of reflux stickies at the top you might have a look at to see if reflux or silent reflux could be the issue.
https://babywhispererforums.com/index.php?board=13.0Silent reflux is when LO rarely spits up a full milk feed but other symptoms and signs are there, they may bring up milk but not all refluxers do.
Meanwhile you can try propping her more upright for sleeping with a cot safe wedge and/or cot blocks and see if that helps. Or hold her more upright and see if she can get some better sleep that way.
I would say that taking only 35 min naps is not normal especially taking into account that you are offering a reasonable length A time and age appropriate routine and using various props and ways of sleeping to try to encourage longer.
They recommend 11pm, because then the baby will sleep for at least 6-7hrs until the morning.
with regards to this. I'm not sure where you are, some countries/cultures have a much later BT and we would not go against a person's culture. There is however a sleep window which comes much earlier than 11pm so we generally do not recommend shifting a routine this late. Instead the usual routine is for baby to go to bed earlier (7 or maybe 8pm) and then to have a dream feed at around 10-10.30pm this is 3 hrs after the BT feed and means that the long stretch of sleep can come after this and when you are sleeping. "sleeping through the night" is classed as 5 hrs, yes it's short, anything beyond that is a bonus. So in effect this is like giving your baby part of the night sleep, then feeding when your friends have said (11pm ish) and then putting to bed for that long stretch. You can get the stretch of sleep for yourself without keeping your baby up so late.
Not all babies will sleep 12hr nights, mine only did 10.5 to 11hrs, but when looking at routine we aim for 12hr nights until we know otherwise and adapt accordingly.
People try to help, but often their help is not where you need it. Many of us have learned to smile and say "thank you". For some I would reply "you had the opportunity to decide XYZ for your child, now I'll decide for my child" not quite as polite but there you go.
By the way - you are not making her sleep habits worse. You are trying to help her sleep which is absolutely the right thing to do. If she was sleeping 2hrs in arms I would be more likely to offer suggestions on how to move her from arms to cot but she isn't. She is showing signs of pain.
I hope this helps. We are here to support you. and on all points only you can decide.