Donating appreciated stock - only want to claim the cost basis

This year (2021) we are donating appreciated mutual funds to a donor advisory fund; we will receive a Form 8283 from the DAF. at the end of the year.  This year we would like to donate more than 30% of our AGI to the DAF in appreciated FMV valued funds.

Is there a way to claim just the cost basis and thereby increase the amount that can be deducted to 50% of our AGI?  How can I keep TT from claiming the full FMV? Will TT recognize that I'm only claiming the cost basis so as not to impose the 30% AGI limit on the deduction?

Thanks!   Old-Tax-Man