I must admit I'm really confused by what you've written. I tried to write it out to see how often you were feeding & how long your Awake times were in the day & I'm still rather confused.
It's not actually abnormal for a BF baby to be fed 3 hourly at night & to have a long unsettled time in the evening from dusk onwards, as that is when Mum's supply is at it's lowest so lots of feeding can be considered normal.
I'm also trying to work out where your "day" starts & finishes ie the times where there is activity time to do things like Tummy time & floor time rather than just feeding & sleeping.
Based on the lots of small feeds, I'd say reflux is probably part of the mix, but looking at what you've written above, I'm having a guess at the start of day was the 8.40am wake up where you have 55mins until the next sleep, which is probably about 10mins (or more) too short & I think that may have a knock on effect, as the big day sleep catches up on night sleep & then the rest of the day looks like the A time might be mostly too short with the exception of the 2nd one which was one hour 40 & then it's 55mins & then 50mins & I can see it all goes to a mess in the evening, where it could be a long unsettled period (not uncommon under 3mo) or maybe because of all short A times he's really not quite tired enough at the end of the day.
I can also see a lot of the sleep times & feeding times overlap, so it's possible that as he's feeding to sleep he's got a sleep association too & so (normal) he expects the same conditions in light sleep stages as he has when he falls asleep. So removing the feed to sleep is pretty important too.
As an idea the "textbook" (although few babies truly match that) would be for an 8week old roughly...
7am up & feed, followed by A time
8 to 8.10 am start to settle for sleep asleep by 8.15/8.30 (can take up to 20mins to settle)
10am up & feed, followed by A time
11ish start to settle for sleep
1pm up & feed, followed by A time
2pmish start to settle for sleep
4pm up & feed, followed by A time
5pmish settle for catnap
6pm up & bath & feed & short A time
7pm ish Settle for night
2 -4 night feeds including Dream feed if done.
Neither of mine did much like that, at 8 weeks old my eldest was still only going 2.5hours between feeds almost around the clock and was unsettled from about 4pm until 11pm, while my youngest was pretty good during the day, but unsettled from 2am to about 5am.