"most amount" is correct and usable in written English.
You can use it to refer to the greatest quantity of something. For example, "I've spent the most amount of money on groceries this month."
"Our sessions are the most amount of fun," she says.
"Does the investment make the most amount of sense?
Teenage girls are not the section of the population having the most amount of sex.
So we try to give them the most amount of time to recover in between".
"The recent attacks... are huge in volume – among the most amount of traffic internet has seen".
It is the last one that gives me the most amount of satisfaction.
"It's our fiduciary duty to sell it for the most amount of money," Brennan said.
Gone, too, are the enormous Norway maples, which provide the most amount of shade.
Plus, he says, It's the piece of furniture you spend the most amount of time in".
Salaries vary according to rank and region but most amount to only several thousands of renminbi.
"Even if we're not the best, we'd still get the most amount of publicity".
