Help, 14m old waking early but needing more sleep

[CaRouleMaPoule]

DS has not long turned 1 and has only recently started sleeping through. However, he now regularly wakes at 5-5:30am but is still clearly tired and will just be grumpy and whiny until he's cuddled and/or breastfed back to sleep for another 45min or so.
He's doing really well at going to sleep in the cot at bedtime and for an afternoon nap, and I think it would be so good for him if he could learn to settle himself back to sleep when he wakes early, instead of us all getting up when none of us are ready to start the day.
I feel like we've tried everything. We've offered water, cows milk, a toy to cuddle. We've tried giving him a quick cuddle and putting him straight back in the cot, we've tried leaving him in the cot but staying in the room to keep him company, we've tried just leaving him to it to see if he eventually runs out of steam. But he just gets more and more worked up until someone comes to get him.
I'd be happy to accept if being an early waker was just his natural routine but he really seems so much happier on the days when he somehow manages to sleep until 6:30/7-ish. On those days he can then go without a morning nap, sleeps well after lunch and is on good form until bedtime at 7:30-8pm.
Any advice? Help!

With Dc1 and Dc2 the thing that helped was to tinker with the evening bedtime. There seemed to be a ‘best bedtime’ with both of them that got us all the most sleep which involved moving bedtime backwards or forwards by about half an hour. There was a somehow suited the child better and allowed us to drop to one nap but have more sleep at night. It just took some trial and error to find it.

Dc3 however has only just stopped getting up at 4.30 every day - we have finally progressed to 5.15. She’s just turned three. You can’t win them all.

I hope my DS takes after your DC1 and 2, not sure I could cope with this if he keeps it up until he's three!

Good idea about moving bedtime around a bit until we find a sweet spot, we'll definitely give that a try. At the moment if he wakes too early it just seems impossible to get him to go back down. So I think the key will be to avoid that by helping him to sleep in for longer if possible.
I just wish I could communicate to him that if he wakes early and is tired enough to fall asleep on us, then he's tired enough to sleep back in his cot for a bit. He's got the hang of it at bedtime and naps, just not in the morning.

Does anyone have any other ideas?

You could try the clock light things sorry can’t remember their name but hes probably too young just yet to Understand it.

I would also have to vote for moving bedtimes...it’s the only thing that worked for us (my DS is 15mnths) it was difficult but I just did it in 15 minutes increments each night. He was wanting to go to bed at 530-6pm each night after nursery and getting up at 5 🙄 now he goes to bed at 7pm and gets up between 630-730 which is such a massive difference to how rested I feel x

We went through a phase of this for about a fortnight with DS at around the same age. It was only a month back. We got him a warmer sleeping bag with sleeves which does seem to have helped - he was waking when the house was at its coldest. We also just rode it out to an extent. They go through so many phases with their sleep, and it won’t last forever even though it feels like it when you’re in it. Good luck OP!

Like @MummaGiles when DD did this at 12m it was because she was cold - we got the heating to come on an hour earlier and she slept til 6.30am