I think all the ad money came from super pacs. DeSantis spent none of the money he raised on ads in NH. He basically skipped the state believing it not his best state to compete in. He hoped with a win in Iowa, the momentum would help him win in NH. His campaign will be studied for generations. He mistakenly listened to those whispering in his ear that Trump was toast with all his legal issues and that 2024 was his year and not 2028. If he wants to make himself viable in 2028, he will need to get out of the race sooner than later.
I know DeSantis did spend substantial money on ads in NH in December—which are not reflected in the January numbers.
He raised a lot of money early and spent it early—and it was not effective in generating decent poll numbers.