I usually undo the bolts that hold the two arms to the bracket that is held by the bolts you circled.
I jack the mower up at the front to give myself plenty of clearance to then slide the deck out.
I use a bit of wire to hold the arms up out of the way to get the deck out.
By unbolting the arms, it won't interfere with the deck adjustment.
If you can undo the bolts you have circled easy enough, that should also work.
Again, you may need to use some wire or such to hold the arms and brackets up to assist in getting the deck out.
You are certainly on the right track. Good luck.
