Do you have a Toni box?
Audio books helped with company for mine.
My poor nighttime sleeper who wasn't an early riser also used audio books for a phase during the night, which isn't ideal but helped with the not feeling alone.
If they share a room that might not work, I can imagine.
My early riser used to "wake" the gro-clock hersel, but a cheap simple kitchen wall clock with masking tape marking the six worked for some reason- trying to touch it was absolutely taboo I guess, as there were other wall clocks in the house and they clearly weren't to be got down! Even my compulsive climber (not the early riser) for whom we had to remove all the furniture from his room and put the mattress on the floor to keep him safe at night, and remove the shelves from the living room book cases etc. never tried to get a wall clock down.
Worth trying different things.
My other child was a good sleeper except when first toilet trained - he didn't want a night nappy once he didn't have one in the day and was amazingly night dry as soon as he was day dry, but the massive down side was then he - my one reliable sleeper - started waking to use the toilet at 5am, only about six months after we'd sorted staying in bed til 6am with the eldest (youngest still up half the night). That was a bit shit and it wasn't as easy to convince him the day didn't start when he woke, I think because he had never woken too early before, plus he was only just 2.5. By 3 I left him to go to the toilet and back to his room without me though 🫣. Might be harder for a small three year old - potty in the bathroom maybe?
It isn't easy, you haven't failed, but there are things you can try, and everything is a phase and different in a year with kids that age...