The apples and oranges that you are mixing up are two different kinds of deductions.
The HSA deduction is a deduction for money that you put IN to the HSA. It has nothing to do with medical expenses that you pay from the HSA or from anywhere else. Technically the HSA deduction is an "adjustment to income." You will see that title at the top of page 2 of Schedule 1. An adjustment is also sometimes called an above-the-line deduction.
When you take money out of the HSA and use it to pay qualified medical expenses, the money you take out is simply not included in your income, so you don't pay tax on it. But it's not a deduction of any kind. It's just not added to your income.
The deduction for medical expenses is an itemized deduction. It's for medical expenses that you pay (that are not covered or reimbursed by insurance). But you don't get to deduct the full amount. 7.5% of your AGI is subtracted from your total unreimbursed medical expenses, and only what's left, if anything, is deducted from your income.
An itemized deduction does not reduce your taxable income unless your total itemized deductions are more than your standard deduction. But an adjustment, or above-the-line deduction, always reduces your income.
