How do I fix a large piece of drywall not matching up on a ceiling repair?
Below is the answer...  But to fix this properly you have to take down
that piece of drywall and give us pictures.   Whatever is behind there
is the issue.   You short-cutted this install and left yourself with
way more work than it should be.   You have not installed proper
backing for this piece or adjoining pieces.   Now you want short-cuts
for your short-cut when taking this piece down and putting backing is
30-45 minutes + scrapwood - NOT OSB!  Also take a look at my last
point (about the texture), as this should be addressed before you
install this piece.

The protrusion or dip in the ceiling is not what concerns me.   The issue is you have no screws in your corners and that your screw schedule is rather random.
Your corners have to be screwed in.   Nothing to screw it in... then put wood up there to make it happen.   This is not negotiable as all of your work will turn to cracks if these corners aren't secure.

If the drywall next to it is missing backing now you need to fix that too.   You cannot float two pieces of drywall next to each other in a ceiling.
The depth issue is due to the lack of backing and bad screw schedule.   Once you fix that, sure it won't be perfect but won't be as bad either.

The other big issue, you are not duplicating that texture and that texture will make it hard to mud/tape the seams.   This is a much bigger issue than your drywall sticking out.