Baby up at 4am every night and only resettles on me

[Berangere]

Baby is 5.5mo and still in snuzpod next to the bed. He wakes every night around 3.30-4.30am, I wake up because I hear him try to resettle himself (getting him to sleep and resettling after a feed he is absolutely fine) by sucking his hands and slamming his legs down. He will be so close to drifting back off and then suddenly he will get himself worked up and shout and squeal.
Popping his dummy back in or just putting my hand on him to ssshh don’t work as he sees me and thinks it’s awake/play time.
If I put him on my chest and pop his dummy back in he will normally go back to sleep very quickly. I’ve tried changing him in case it’s his nappy bothering him, but it’s not that, and it’s not normally hunger as he often goes straight back to sleep but on me.
He’s currently been up almost 2 hours because as soon as I put him back in his snuzpod he gets worked up and awake and we start all over again.
He still has 3-4 naps a day totaling around 3 hours, and bedtime is normally around 8, though tonight was later due to us having house viewings. We don’t have much of a daily routine as I’m very led by his wake windows and making sure he’s tired enough to sleep.
We want to put him in his own room at 6mo but if he’s still having these wakings i don’t see the point…
I don’t know what I’m doing wrong! He does sometimes sleep through and I rack my brain trying to work out what we did differently. Is this developmental or is there anything I can do to fix it? I’m exhausted from being up every night and resorting to letting him sleep on me.

You're not doing anything wrong.
My DC's sleep patterns changed lots from 4 to 5m.o. We had a similar set up to you, and similar pattern to what you're describing. I just got used to letting him sleep on me from 4 or 5, and actually was able to sleep half sitting up alot of the time. Otherwise I'd listen to podcasts or read on my phone. Quite liked the quiet time to myself.
But if that doesn't work for you I think your little one will learn to resettle in time, or shift to another stage with completely different sleep patterns! I remember being told they're completely transformed creatures every 8 weeks in the first few years.

That kind of time can be the coldest time at night, could it be a temperature drop that's making it harder for him to settle back then in winter?

All sounds normal to me. In fact going until 3.30 sounds amazing. My 5 month old starts his only sleeping on me routine from about 12 lately, then I usually take him downstairs to not disturb anyone and let him sleep on me reclined on the sofa. Not great but I'm banking on things improving at 6 months.

I know you say it's not hunger but milk would very likely send him back into a deeper sleep so you can put him back down. Either that or just do the last stretch of the night with him in bed with you.

Hiya. Did you ever find a solution to this?? This sounds exactly like my 6month old. Wakes up at 4am on the dot but will go back to sleep straight away on me.

When you put him back in the cot, it’s cold opposed to your warm body

do you have a white noise machine? This might help him settle again before lifting him