Everyone has given the advice I would so all I can say is that when they are teenagers you could be asking how to wake them up!!!

My first two were dreadful at night so I can empathise! Seems a long time till they are teenagers at the moment!!
I had 4 years of sleep deprivation then had a little one who slept like other mums tell you theirs do!

And there was no magic recipe that I can think of except that I expected no sleep and was more relaxed with him??

He is still the most easygoing ofd the three. Anyway

from me and hope it improves soon.