10 month sleeping schedule Q

It took forever for my son ( our 2nd) to finally start sleeping through the night. I get it all kids are d different I am just looking for recommendations for people that have delt with similar and found solutions. So my son it doesn’t matter if he goes to sleep at 6,7 or 8pm he is up at 6 on the dot everyday. His bedtime right now is 7:30pm. I thought putting black out curtains would help but it didn’t. He just wants me and wil scream until he gets what he wants. And he never just wakes up he wakes up screaming /howling.