Help! My 6 months old is refusing to sleep

My baby is going to be 6 months next Tuesday

He wasn’t a good sleeper since the beginning but with consistency and good routine he slept during night and napped very well

Now since few days he became really fussy and refuses to sleep

And keeps screaming and cooing as if he’s discovering his voice lol

And also keeps trying to roll over and sit

And if he sleeps he wakes up at 4 or 5 am!!

Nothing is working to put him to sleep

He keeps practicing whatever he wants until he gets tired and sleep!

We tried rocking co sleeping

We even did ferber method for 3 days last week which failed and then tried the chair method also failed and according to our sleep consultant we should stop then try again after he is 6 months officially

Regarding teething I don’t see obvious signs but I think he is because also he became extremely fussy

Me and his dad we literally feels like zombies

Did anyone also passed by such scenario at 6 months?

And what did you do? To pass through it smoothly 😅❤️