the standard deduction, you should bunch your donations. Essentially the difference is the opportunity to save on taxable income.
I think that is what you said in your last sentence, that your SALT plus mortgage interest exceeds your standard deduction. If so, there isn't a benefit to bunch from a tax deduction standpoint.
I worked up a little spreadsheet where you can input your specifics - if you want it, send me a board mail with your email and I will send it to you.