Spalletti was the guy who wanted and signed him, but he resigned before the season started, Garcia took over and lasted until November, replaced by Materazzi who lasted until February replaced by Calzona who left in the summer. Spalletti played an attacking 4-3-3 - so he'd have been playing a similar position to at Frankfurt as they didn't play wingers
I also read that here, it's what that Lindstrom expert/blogger told everyone but then Spalletti left Napoli in May 2023. Lindstrom signed for Napoli in August 2023.
Other than the commentary from the same PR bloke when he signed - I struggled to find any ref to Spalletti/Lindstrom, or even ref to any pre agreement. I dont think it exist, because he signed late in that summer transfer window.
The window shuts in Italy 30th Aug. He signed on 29th Aug.
So he signed for Napoli, and evidently wasn't fancied by Garcia, Mazzarri or Calzona.