New day new problems...
Don't be despondent, not yet anyway...
If you are going further with this engine, you will need a flywheel puller bolt, same size and thread as the oil filter bolt, which you take to your bolt shop for comparison. Get a long bolt. The bolt I use is about a foot long.
Get or make a clutch nut socket there is a thread on here of how to make it. I know one person on here who made one very recently, anoloqueliz.
Do not remove engine from frame untill the flywheel retaining bolt has been removed along with flywheel and stator, and clutch nut slackened.
The bike provides a steady mass which will help you along with means of preventing things from moving/rotating.
You have given your self a problem by removing cyl head meaning the cam chain will be compromised unless care is taken.
Get an assistant to hold the cam chain up and tight, so if flywheel rotates, the cam chain cannot bunch up and damaged, whilst the flywheel retaining bolt is undone and removed.
Clutch nut, assistant holds cam chain up and tight, bike in high gear, apply rear brake and undo the clutch nut with your socket.
Then you can remove the engine.
In your first thread someone mentioned the clutch nut was on backwards, meaning engine had been apart before.
Maybe due to broken starter clutch due to hydraulic lock due to carbs leaking ???
You have gone this far. You have a warm dry well lit organised work space. You do, with some guidance probably, have the skills and cautious determination to take this engine apart, hopefully repair, and successfully reassemble.
For course you will not know the full extent of damage untill you take the engine apart for assessment.
Your bike, your time, your money, your decision.
I know the forum will help, it's why it's here.