The best thing to do when working n these is to drop the deck then stand the mower up on it's bum
Then you can get a spannar behind the bolt to hold the head.
What you have to remember is a semi skilled production line worker made the mower so it can be unmade by any one with a small amount of knowledge, patience and skill.
Knowledge starts with going to a web site & getting your hands on the IPL so you know your enemy .
As luck would happen the IPL for a YTH22V46 was still on my hard drive so it will appear below
You will see a bolt # 121 in the diagram and notice where the head is.
Two ways to get at it
Drill a hole which is what every one recommends or put you finger on top of the bolt to hold the head which is what I have managed to do without much problem about 200 or so times .
From the diagram you will see that it is a coach bolt so it is captive as long as you hold the head down.
This means you need to use a hand held wrench and turn it with your arms & not an electric device .
Not a big deal when you take your time & have a think about it.
As already advised replace all 3 pulleys & the belt while you are there and it will be done for another 5 or more years.