I found the below in Cambridge Dictionary web-site:

We use much in questions and negative clauses to talk about degrees of something.

We don’t use much in affirmative clauses.

Also, it the same web-site, I found the following:

She runs much faster than he does. here

also I noticed that some web-sites use much with affirmative clauses:

May we all be having this much fun and getting this much exercise when we're his age! PJ Media

Is it Okey to use much in affirmative clauses? If yes, when can we use it? and what is the rules?