Baby led routine

My DS is 4 months old and we have ended up on a very baby led routine. It wasn't really intentional, his big sister thrived on routine. But when I tried to put him in any kind of routine we all just ended up miserable. His food/sleep needs seem hugely variable so it seems easier to go with the flow and do my best to follow his cues as to when he's hungry/tired. His bedtime can be anywhere from 7pm - 9.30pm depending on what time his last nap is. Some days he has lots of little cat naps, other days he has less longer naps. The only predictable thing is he always tends to wake around 6.45am as that's when my older DD comes into our room and she's not always the quietest!! I know this variability is probably against all the guidance about "good sleep" but to me feels better than lots of crying trying to get into a routine he clearly doesn't want. At the moment his night sleep is OK, but I realise that could change and if it does I might have to rethink my approach.

My question is for other people that had a very baby led approach, when did they settle into their own pattern and become a bit more predictable? I don't mind for now, but at some point I'd like to have more of an idea of when he's likely to sleep, how long for and when he'll be ready for bed. Even just vaguely would be nice!

Also, any tips on handling the clock change in a couple of weeks? I feel like I have no ability to manipulate his sleep, so we are going to be on 5.45 wake ups for the foreseeable future as that's when he is used to waking up. But I think if I try and keep him up later to then push wake ups later he will end up miserable or just conk out earlier anyway.

I can't help having a vague feeling I'm doing this wrong, although we all seem happy enough at the minute.