Yes, you can have your clients donate directly to a charity and then you will not pay taxes on the amount or deduct it on your return.
As a self-employed business, your business is not separate from your personal for taxes. So, items that are not business in nature are treated as they would be at the personal level, which includes charitable deductions. You are understanding correctly, they are only deducted as itemized deductions.
While not beneficial in this situation, there are many benefits of having business taxes be simplified in this way.
